Question 1

Chinese scientists cloned two identical long tailed macaque monkeys using a laboratory method that involved transferring the nucleus of a body cell into an enucleated egg cell. By which cloning process was this achieved?

Accepted Answer

Introduction / Context: Cloning of mammals such as sheep, cats and now monkeys has usually relied on specific nuclear transfer techniques. One famous method, used to create Dolly the sheep, is called somatic cell nuclear transfer. In this approach, the nucleus of a differentiated body cell is placed into an egg cell whose own nucleus has been removed. Chinese scientists used a similar strategy to clone two identical long tailed macaques. This question asks you to identify the correct name of the cloning process used. Given Data / Assumptions: The cloned animals were long tailed macaque monkeys, a type of primate. The description refers to transferring a nucleus from a body (somatic) cell into an enucleated egg cell. Polymerase chain reaction is a molecular technique for amplifying DNA, not a whole animal cloning method. Parthenogenesis is development of an egg without fertilisation, and embryonic cell nuclear transfer uses embryonic nuclei rather than differentiated somatic nuclei. Concept / Approach: Somatic cell nuclear transfer is a cloning technique where the nucleus from a somatic (non reproductive) cell is inserted into an egg cell that has had its own nucleus removed. The reconstructed egg is then stimulated to divide and develop into an embryo, which can be implanted into a surrogate mother. This method produces an animal genetically almost identical to the donor of the somatic nucleus. Polymerase chain reaction is used instead to create many copies of a DNA segment. Parthenogenesis involves egg development without fertilisation and does not require nuclear transfer, and embryonic cell nuclear transfer uses nuclei from embryonic cells rather than from fully differentiated somatic cells. The reports on cloned macaques specifically mention somatic cell nuclear transfer as the approach used. Step-by-Step Solution: Step 1: Identify that the question describes a process where a nucleus from a body cell is transferred into an enucleated egg cell. Step 2: Recall that such a process is characteristic of somatic cell nuclear transfer, a technique used for cloning whole animals. Step 3: Consider option a, polymerase chain reaction, and remember that this is a DNA amplification method used in test tubes, not an embryo cloning method. Step 4: Consider option b, parthenogenesis, which involves an egg developing without fertilisation but does not involve nuclear transfer from a somatic cell. Step 5: Distinguish option c, somatic cell nuclear transfer, from option d, embryonic cell nuclear transfer, and select somatic cell nuclear transfer because the question emphasises body cells rather than embryonic cells. Verification / Alternative check: Descriptions of the cloning of the long tailed macaques explain that researchers took nuclei from fibroblast cells, which are somatic cells, and introduced them into enucleated egg cells. This method is clearly labelled somatic cell nuclear transfer and is widely compared to the process used for Dolly the sheep. In such reports, polymerase chain reaction is mentioned only as a laboratory tool for verifying genetic identity, not as the cloning method itself. Parthenogenesis and embryonic cell nuclear transfer are described in different contexts and do not match the procedure described for these monkeys. Why Other Options Are Wrong: Option a, polymerase chain reaction, is used to amplify DNA fragments in vitro and cannot by itself produce cloned animals. Option b, parthenogenesis, is a natural or induced process where an egg develops into an organism without fertilisation, and it does not involve transferring a nucleus from a somatic cell. Option d, embryonic cell nuclear transfer, uses nuclei from embryonic cells rather than from fully differentiated somatic cells, which does not match the body cell description in the question. Common Pitfalls: Students may see the word nuclear transfer and quickly pick any option containing nuclear without reading the full description of somatic versus embryonic cells. Others may confuse commonly heard terms like polymerase chain reaction with cloning methods because both are molecular biology techniques. To avoid these errors, focus on the source of the nucleus mentioned in the question. If it clearly refers to a body cell, the method is somatic cell nuclear transfer, which is the classic cloning technique used in these high profile experiments. Final Answer: The macaque monkeys were cloned by Somatic cell nuclear transfer.

Question 2

In soil conservation, the method in which different crops are grown in alternate rows or strips and are sown at different times to reduce soil erosion and protect the soil from being washed away by rain is called what?

Accepted Answer

Introduction / Context: Soil erosion by water is a major agricultural problem, especially on sloping land or in areas with heavy rainfall. To reduce erosion, farmers and conservationists use several soil conservation techniques. One of these methods involves planting different crops in alternating rows or strips and staggering their sowing times so that the soil surface is always well protected by vegetation. This question asks you to identify the correct name of that method from among several commonly mentioned soil conservation practices. Given Data / Assumptions: The method uses different crops grown in alternate rows or strips. Crops may be sown at different times to ensure continuous cover and reduce rain impact. The main goal is to protect the soil from being washed away by rain water. Other methods like mulching, rock dams and terrace farming are also known soil conservation techniques but have different characteristics. Concept / Approach: Strip cropping is a soil conservation method in which different crops are grown in long, narrow strips across the slope of the land. Often, erosion resistant crops such as grasses or legumes alternate with erosion prone crops such as maize or cotton. When rain falls, the strips of dense vegetation slow down water flow and trap soil, reducing erosion. By sowing different crops at different times, farmers maintain continuous cover on some strips even when other strips are bare or newly planted. Mulching involves covering the soil with plant residues or plastic, rock dams slow water flow in gullies and terrace farming converts steep slopes into steps. None of these other methods match the description of alternating rows of different crops as clearly as strip cropping does. Step-by-Step Solution: Step 1: Focus on the key description in the question: different crops grown in alternate rows and sown at different times to protect soil from rain wash. Step 2: Recall that strip cropping specifically involves growing crops in alternate strips across the slope to check soil erosion. Step 3: Consider mulching, which uses straw, leaves or other materials spread on soil, but does not necessarily involve alternating crops. Step 4: Recognise that rock dams are small stone barriers placed in channels to reduce water speed, and terrace farming shapes the land into stepped fields, both very different from alternating crop strips. Step 5: Match the described method to strip cropping and choose the option that explicitly mentions alternate rows of different crops as the correct answer. Verification / Alternative check: Agriculture and soil science textbooks describe strip cropping as growing two or more crops in strips on the same field, often oriented at right angles to the direction of wind or water flow. Illustrations show alternating strips of tall and short crops, or of cereals and grasses, which break the force of wind or water and reduce erosion. In contrast, mulching is shown as a blanket of residue on soil, rock dams are structures in gullies and terrace farming involves cutting broad steps into hillsides. These descriptions confirm that the technique of alternating different crops in rows and sowing them at different times to reduce rain wash is called strip cropping. Why Other Options Are Wrong: Option a, mulching, protects soil by covering it with organic or synthetic materials, but it does not involve growing different crops in alternate strips. Option c, rock dam, involves placing rocks in drainage channels to slow water, which is a structural measure rather than a cropping pattern. Option d, terrace farming, reduces erosion by modifying the shape of hilly land into flat steps, not by alternating crop rows on the same slope. Common Pitfalls: Learners sometimes confuse strip cropping with terrace farming because both are associated with soil conservation on slopes. Another common mistake is to choose mulching whenever they see the word protect soil without checking the specific method described. To avoid these errors, focus on whether the technique involves changing the cropping pattern or changing the physical shape of the land or covering the soil with mulch. The description of alternating crops in rows matches strip cropping, making it the correct choice for this question. Final Answer: The soil conservation method described is called Strip cropping, where different crops are grown in alternate rows or strips.

Question 3

In ecology, __________ is the type of interaction between two species in which one species benefits while the other species is neither harmed nor benefited in any significant way.

Accepted Answer

Introduction / Context: Species in an ecosystem interact with each other in many different ways, ranging from cooperation to competition and exploitation. Ecologists classify these interactions based on how each species is affected in terms of benefit, harm or neutrality. This question asks you to identify the specific type of interaction in which one species gains a benefit while the other species is essentially unaffected, experiencing neither significant harm nor benefit. Given Data / Assumptions: One species clearly benefits from the relationship. The other species is neither harmed nor helped; its fitness remains largely unchanged. The interaction is stable enough to be recognised as an ecological relationship. We are choosing between common interaction types: predation, commensalism, competition and parasitism. Concept / Approach: Commensalism is defined as an interaction between two species where one species benefits and the other is neither harmed nor helped. Examples include birds building nests in trees, where the bird gains shelter and the tree is generally unaffected, and epiphytic plants growing on branches of larger trees without drawing nutrients from them. In predation, one species benefits while the other is harmed. In competition, both species are negatively affected by the interaction as they compete for limited resources. In parasitism, one species benefits at the expense of the other, which is harmed. Therefore, the only term that matches the pattern one benefits, other unaffected is commensalism. Step-by-Step Solution: Step 1: Translate the question description into ecological notation: one species benefits, the other is neutral, which can be written as plus and zero. Step 2: Recall that commensalism is often represented as plus and zero because one species gains and the other is unaffected. Step 3: Consider predation, which is plus and minus; the predator benefits while the prey is harmed or killed. Step 4: Consider competition, which is minus and minus; both species experience reduced growth or reproduction due to shared limited resources. Step 5: Consider parasitism, which is plus and minus; the parasite benefits while the host is harmed, and choose commensalism as the only interaction matching plus and zero. Verification / Alternative check: Ecology textbooks list major interspecific interactions and often summarise them in a small table showing effects on both species. In that table, commensalism is consistently described as a relationship in which one partner benefits and the other experiences no significant effect. Examples such as remora fish hitching rides on sharks or cattle egrets feeding on insects disturbed by grazing cattle illustrate this pattern. Predation and parasitism are shown as interactions where the host or prey is harmed, and competition is shown as harmful to both. This consistent presentation confirms that commensalism is the correct term for the interaction described in the question. Why Other Options Are Wrong: Option a, predation, involves one species eating another, clearly benefiting the predator while harming the prey, which is not neutral. Option c, competition, reduces the success of both species because they vie for the same limited resources, so neither is neutral. Option d, parasitism, benefits the parasite but harms the host by stealing nutrients or causing disease, which again does not match the description of the second species being unaffected. Common Pitfalls: Students may confuse commensalism with mutualism or parasitism because all involve close living arrangements. A useful trick is to remember that in mutualism both species benefit, in parasitism one benefits and one is harmed, and in commensalism one benefits while the other experiences no significant effect. Another pitfall is to assume that any minor change must count as harm or benefit, but ecologists focus on significant, consistent effects on survival and reproduction when classifying interactions. Final Answer: The interaction where one species benefits and the other is neither harmed nor benefited is called Commensalism.

Question 4

In botany, Azadirachta indica is the scientific (binomial) name of which commonly known tree species that is widely used in traditional medicine and as a natural pesticide?

Accepted Answer

Introduction / Context: Scientific names provide a standard way to identify plant and animal species across different languages and regions. Each scientific name, or binomial, consists of a genus and a species name. Azadirachta indica is a well known example in Indian botany and traditional medicine. This question asks you to match this scientific name with the correct common name of the tree from a list of familiar species. Given Data / Assumptions: Azadirachta is the genus, and indica is the species epithet, indicating an association with India. The options list several common trees and a herb widely known in India. Neem is a tree with many medicinal and pesticidal uses, while teak and silver oak are timber trees and tulsi is a herb. We assume basic exposure to common scientific names in school biology. Concept / Approach: Azadirachta indica is the botanical name for the neem tree, a hardy evergreen tree commonly found in India and other tropical regions. Neem leaves, bark, seeds and oil are widely used in traditional medicine and as a natural pesticide. Teak, used for timber, has the scientific name Tectona grandis. Silver oak is typically known as Grevillea robusta, and tulsi, a sacred basil, is usually referred to as Ocimum tenuiflorum or Ocimum sanctum. By matching Azadirachta indica with the correct common name, we identify neem as the correct option among those listed. Step-by-Step Solution: Step 1: Recall that Azadirachta indica is a scientific name frequently cited in discussions of medicinal plants and bio pesticides. Step 2: Associate Azadirachta indica with the neem tree, which is known for its bitter leaves and wide range of traditional uses. Step 3: Consider teak and remember that its scientific name is Tectona grandis, which does not match Azadirachta indica. Step 4: Recognise that silver oak has a different scientific name, often given as Grevillea robusta, and tulsi is an herb with the genus name Ocimum, not Azadirachta. Step 5: Conclude that neem is the only correct match for Azadirachta indica among the options provided. Verification / Alternative check: Plant taxonomy references and medicinal plant guides consistently list Azadirachta indica as the scientific name for the neem tree. Descriptions highlight neem as a fast growing tree with pinnate leaves and small white flowers, with various parts used in traditional remedies and in organic farming. Teak and silver oak are listed under different genera and species in timber manuals, while tulsi appears in herbal guides under Ocimum. These independent sources align in naming Azadirachta indica as neem, confirming the correct choice. Why Other Options Are Wrong: Option b, teak, is a valuable timber tree known scientifically as Tectona grandis and is unrelated to the genus Azadirachta. Option c, silver oak, is an ornamental and timber tree often called Grevillea robusta and does not share the Azadirachta genus. Option d, tulsi, is a herb used in traditional medicine and worship, with scientific names such as Ocimum tenuiflorum, so it does not match Azadirachta indica. Common Pitfalls: Learners sometimes guess based on geographic hints such as indica and mistakenly connect the name to any familiar Indian plant like tulsi, without checking the genus. Others may confuse neem and teak because both are common trees in India and both are used in rural life. To avoid these errors, it helps to memorise a small core list of scientific names, including Azadirachta indica for neem, Mangifera indica for mango and Punica granatum for pomegranate, and use them as reference points in exams. Final Answer: Azadirachta indica is the scientific name of the Neem tree.

Question 5

In film and general knowledge, who played the role of Mahatma Gandhi in the 1982 Oscar winning biographical movie titled Gandhi?

Accepted Answer

Introduction / Context: The 1982 film Gandhi is a widely acclaimed biographical movie that portrays the life and philosophy of Mahatma Gandhi, the leader of the Indian independence movement. The film won multiple Academy Awards and featured a remarkable performance in the title role. This question asks you to recall which actor played Gandhi in that film, an item that often appears in general knowledge and film related quizzes. Given Data / Assumptions: The film Gandhi was released in 1982 and went on to win Oscars, including awards for acting and direction. Ben Kingsley is a well known actor recognised for portraying Gandhi. Saeed Jaffrey acted in many films but did not play Gandhi in this movie. Marlon Brando was a famous Hollywood actor known for other roles, and Richard Attenborough was the director of Gandhi. Concept / Approach: Ben Kingsley played the role of Mahatma Gandhi in the 1982 film and received widespread critical acclaim for his performance, including an Academy Award for Best Actor. Richard Attenborough directed the film and is often associated with it, which can cause confusion, but he did not portray Gandhi on screen. Saeed Jaffrey had supporting roles in various international films, and Marlon Brando is known for classic performances in other movies, not for playing Gandhi. By matching the film title, the release year and the role, we can identify Ben Kingsley as the correct actor. Step-by-Step Solution: Step 1: Recall the 1982 biographical film Gandhi, which focuses on the life of Mahatma Gandhi. Step 2: Remember that the actor who played Gandhi in this film is Ben Kingsley, who won the Academy Award for Best Actor for this role. Step 3: Check option a and see that it lists Ben Kingsley, matching your recollection. Step 4: Consider option d, Richard Attenborough, and recall that he directed the film but did not act as Gandhi. Step 5: Recognise that Saeed Jaffrey and Marlon Brando are accomplished actors but are not associated with the title role in this specific movie, confirming Ben Kingsley as the correct answer. Verification / Alternative check: Film history references and lists of Academy Award winners show Ben Kingsley winning the Best Actor award for his portrayal of Mahatma Gandhi in Gandhi at the 55th Academy Awards. Richard Attenborough is credited as the director and also received awards for his work behind the camera. Cast lists for the film confirm that Ben Kingsley is credited in the title role, while Saeed Jaffrey appears in a supporting role and Marlon Brando is not part of the cast. These details align with the recognition of Kingsley as the actor who played Gandhi in the 1982 film. Why Other Options Are Wrong: Option b, Saeed Jaffrey, is a respected actor who appeared in many international productions but did not play the title role of Gandhi in this film. Option c, Marlon Brando, is known for roles in films such as The Godfather and A Streetcar Named Desire, not for portraying Gandhi. Option d, Richard Attenborough, directed Gandhi and is praised for his direction, but he did not appear as Mahatma Gandhi in the movie. Common Pitfalls: Some learners confuse the director of a famous film with its lead actor, especially when both are frequently mentioned together in award discussions. Others may recall that several Indian actors participated in the project and mistakenly choose one of them. To avoid such confusion, it helps to memorise the pairing of Ben Kingsley as the actor portraying Gandhi and Richard Attenborough as the director of the film Gandhi, and to recognise this combination as a common general knowledge question. Final Answer: The role of Mahatma Gandhi in the 1982 Oscar winning film Gandhi was played by Ben Kingsley.

Question 6

In basic astronomy, excluding the Sun itself, which star is currently recognised as the closest known star to our solar system and to the Sun?

Accepted Answer

Introduction / Context: Stars in our galaxy are at vast distances from the Sun, but a small group of nearby stars form our stellar neighbourhood. General knowledge questions often ask which star, other than the Sun, is the closest to our solar system. Although several names such as Alpha Centauri and Barnard star are frequently mentioned, only one star currently holds the record as the closest known star to the Sun. This question tests whether you can identify that star from a short list of possibilities. Given Data / Assumptions: The question explicitly excludes the Sun and asks for the closest star to our solar system. Alpha Centauri is a star system, including a bright binary pair and a faint red dwarf companion. Beta Centauri and Barnard star are also relatively nearby, but at greater distances. The focus is on the single star that is closest in terms of distance from the Sun. Concept / Approach: The Alpha Centauri system consists of Alpha Centauri A, Alpha Centauri B and a small red dwarf known as Proxima Centauri. Proxima Centauri is slightly closer to the Sun than the brighter pair and is therefore recognised as the closest known star to our solar system, at a distance of a little over four light years. Alpha Centauri A and B, although very close in astronomical terms, are slightly farther away than Proxima Centauri. Beta Centauri and Barnard star are also nearby but lie at greater distances. Therefore, Proxima Centauri is the correct answer when asked for the closest star to the Sun apart from the Sun itself. Step-by-Step Solution: Step 1: Recall that the Sun is the closest star to Earth, but the question asks for the closest star other than the Sun. Step 2: Remember that Proxima Centauri is a red dwarf star that is part of the Alpha Centauri system and lies slightly closer to the Sun than Alpha Centauri A and B. Step 3: Identify option c, Proxima Centauri, as the star widely known to hold the record for being the nearest star to the Sun. Step 4: Note that Alpha Centauri in option a usually refers to the bright binary pair, which is slightly farther than Proxima Centauri, even though they are part of the same overall system. Step 5: Recognise that Beta Centauri and Barnard star are more distant stars and therefore cannot be the closest, confirming Proxima Centauri as the correct answer. Verification / Alternative check: Astronomical data tables list distances to nearby stars in light years or parsecs. Proxima Centauri is given as roughly 4.24 light years from the Sun, while Alpha Centauri A and B are slightly farther away. Barnard star is about 6 light years away, and Beta Centauri is farther still. Various educational diagrams of the local stellar neighbourhood label Proxima Centauri as the nearest star, often grouping it with Alpha Centauri A and B as a triple system. These consistent references confirm that Proxima Centauri is the closest known star to our solar system other than the Sun. Why Other Options Are Wrong: Option a, Alpha Centauri, often refers to the bright pair Alpha Centauri A and B, which are a little more distant than Proxima Centauri. Option b, Beta Centauri, is a bright star in the constellation Centaurus but is farther away than the Alpha Centauri system and Proxima Centauri. Option d, Barnard, refers to Barnard star, a red dwarf in the constellation Ophiuchus, which is relatively close but still more distant than Proxima Centauri. Common Pitfalls: Learners sometimes assume Alpha Centauri must be the closest because it is widely known and bright, overlooking that Proxima Centauri, though much dimmer, is slightly nearer. Another pitfall is to forget that the question excludes the Sun and to think of the Sun as an answer, which is not allowed here. Keeping in mind that Proxima Centauri is the faint but nearest neighbour helps answer this frequently asked question correctly. Final Answer: The closest known star to our solar system, apart from the Sun, is Proxima Centauri.

Question 7

In basic astronomy and general science, which planet in our solar system is popularly known as the red planet because of its reddish appearance when viewed from Earth?

Accepted Answer

Introduction / Context: Planets often have popular nicknames based on their appearance or other distinctive characteristics. One of the most famous is the red planet, a term frequently used in schoolbooks, science magazines and media reports. This question asks you to recall which planet in our solar system is commonly referred to by this nickname and to distinguish it from other planets that may also appear bright or coloured in the night sky. Given Data / Assumptions: The nickname red planet refers to the overall reddish colour of the planet as seen from Earth. Mars has a surface rich in iron oxides, giving it a reddish appearance. Mercury and Venus are bright but do not appear distinctly red; Pluto is a distant dwarf planet and is not typically associated with this nickname. The question is concerned with common general knowledge usage rather than detailed spectral data. Concept / Approach: Mars is widely known as the red planet because its surface contains iron rich minerals that have oxidised, giving it a rusty reddish colour. This hue makes Mars stand out in the night sky as a reddish point of light. Mercury appears more greyish and is often difficult to see, Venus appears as a bright white or yellowish evening or morning star, and Pluto is too faint to be seen without telescopes and is usually classified as a dwarf planet. Because of its distinct colour and widespread cultural recognition, Mars is the only planet commonly called the red planet in both scientific and popular contexts. Step-by-Step Solution: Step 1: Recall that Mars has a reddish surface due to iron oxide rich dust and rocks, which is why it is popularly called the red planet. Step 2: Consider the appearance of Mercury, which is small and greyish, not strongly red when viewed from Earth. Step 3: Note that Venus is very bright but appears more white or yellowish than red. Step 4: Recognise that Pluto is a distant dwarf planet and is not commonly associated with the nickname red planet in school level general knowledge. Step 5: Select Mars as the planet widely and consistently known as the red planet. Verification / Alternative check: Science textbooks, documentaries and space agency materials refer to Mars as the red planet because of its colour and the dusty iron rich surface. Space missions such as orbiters and rovers sent to Mars are often described as exploring the red planet. Planetary identification charts and classroom posters also label Mars with this nickname. No similar widespread nickname associates Mercury, Venus or Pluto with the phrase red planet, confirming that Mars is the intended and correct answer in this question. Why Other Options Are Wrong: Option a, Mercury, is close to the Sun and appears as a small greyish or slightly yellowish point, not distinctly red, and is not known as the red planet. Option b, Pluto, is now classified as a dwarf planet and is not visible to the unaided eye, nor commonly nicknamed the red planet. Option d, Venus, is often called the morning star or evening star due to its brightness and white or yellowish appearance, not for any red colour. Common Pitfalls: Learners might confuse Mars with Venus because both are visible and sometimes bright, but only Mars appears strongly reddish. Others may be influenced by images of distant trans Neptunian objects with varied colours and mistakenly think of Pluto or other bodies. Anchoring the nickname red planet firmly to Mars and remembering its rusty surface from rover photographs helps to avoid such confusion in exams and quizzes. Final Answer: The planet known as the red planet is Mars.

Question 8

In health and general science, the term Ebola is commonly used in news and medical reports. What does the term Ebola refer to in this context?

Accepted Answer

Introduction / Context: Ebola is a term that has appeared frequently in global news, particularly during major outbreaks in parts of Africa. Understanding what Ebola refers to is important for basic health awareness and general knowledge. Although the name originally comes from a river in central Africa, in modern usage it is strongly associated with a severe viral disease that caused significant outbreaks, especially in West Africa in the twenty first century. This question asks you to select the description that best matches this widely used term. Given Data / Assumptions: Ebola refers to a viral haemorrhagic fever caused by the Ebola virus. Large, widely reported outbreaks have occurred in several West African countries. The question options refer to specific regions and alternative meanings such as a city or a different outbreak. The focus is on common general knowledge usage rather than detailed virology or geography. Concept / Approach: The term Ebola, in general news and health reports, refers to Ebola virus disease, a severe and often fatal illness in humans caused by the Ebola virus. Major outbreaks took place in West African countries such as Guinea, Liberia and Sierra Leone, drawing global attention. The disease is characterised by fever, weakness, vomiting, diarrhoea and sometimes internal and external bleeding. While the name originates from the Ebola River in what is now the Democratic Republic of the Congo, the best match among the options is the description of a viral disease outbreak in West Africa caused by the Ebola virus. It is not associated with Bangladesh or a specific city in Syria in common usage. Step-by-Step Solution: Step 1: Recall that Ebola is a viral disease, not the name of a city or a different kind of disaster. Step 2: Remember that one of the largest and most widely reported outbreaks of Ebola virus disease occurred in West Africa in the twenty first century. Step 3: Examine option a, which correctly describes Ebola as a viral disease outbreak in West Africa caused by the Ebola virus. Step 4: Check option b, which incorrectly associates Ebola with Bangladesh, a country not known for major Ebola outbreaks. Step 5: Consider option c, which wrongly describes Ebola as a city in Syria, and recognise that option d, none of these, cannot be correct because option a already provides an accurate description. Verification / Alternative check: Health organisation reports and educational materials describe Ebola virus disease as an acute, serious illness often fatal if untreated. They document major outbreaks in African countries, with a particularly notable outbreak in West Africa that led to global emergency responses. Maps and timelines of these outbreaks highlight regions such as Guinea, Liberia and Sierra Leone rather than Bangladesh or Syria. While the origin of the name is tied to a river, common usage today centres on the disease itself and its outbreaks. This confirms that the option mentioning a viral disease outbreak in West Africa is the best match for the term Ebola in a general knowledge context. Why Other Options Are Wrong: Option b, a viral disease outbreak in Bangladesh, is incorrect because Ebola outbreaks have not been centred in Bangladesh in widely reported history. Option c, a city in Syria destroyed by conflict, confuses the name with locations and events unrelated to Ebola virus disease. Option d, none of these, is wrong because option a already correctly captures the nature of Ebola as a viral disease associated with major West African outbreaks. Common Pitfalls: Learners may be aware that the name Ebola originally comes from a river in central Africa and might look for that detail in the options, but examination questions often simplify the description to focus on well known outbreaks. Others might confuse Ebola with other diseases or conflict related news due to intense media coverage of different crises. Keeping in mind that Ebola refers to a viral haemorrhagic fever and that the most publicised outbreaks were in West Africa helps to select the correct option confidently. Final Answer: In general usage, Ebola refers to a viral disease outbreak in West Africa caused by the Ebola virus.

Question 9

Mangifera indica is the scientific (binomial) name of which commonly cultivated fruit tree that is widely known as the king of fruits in many regions?

Accepted Answer

Introduction / Context: Scientific names allow scientists and students to refer to plant species precisely, avoiding confusion caused by different local names. Mangifera indica is one of the most commonly cited scientific names in basic botany, especially in regions where the associated fruit is very popular. This question asks you to match Mangifera indica with its correct common fruit name from a list of familiar fruits. Given Data / Assumptions: Mangifera is the genus name, indicating a group of related trees. Indica suggests an association with India or the Indian subcontinent, where the tree is widely grown. The options list guava, mango, amla and jack fruit, all common fruits in South Asia. The fruit traditionally called the king of fruits in many parts of India is the mango. Concept / Approach: Mangifera indica is the botanical name for the mango tree, a tropical evergreen tree that produces sweet, fleshy fruits. The genus Mangifera includes several species, but Mangifera indica is the domesticated species most widely cultivated for its fruit. Guava is known scientifically as Psidium guajava, amla as Phyllanthus emblica or Emblica officinalis, and jack fruit as Artocarpus heterophyllus. Matching these scientific names with the correct common names shows that Mangifera indica must correspond to mango among the given options. Step-by-Step Solution: Step 1: Recall that Mangifera indica is frequently mentioned in school botany as the scientific name of mango. Step 2: Associate the genus Mangifera with mango trees, including the many cultivated varieties grown in orchards. Step 3: Recognise that guava belongs to the genus Psidium, which eliminates option a. Step 4: Remember that amla is often given the scientific name Phyllanthus emblica or Emblica officinalis, and jack fruit is identified as Artocarpus heterophyllus. Step 5: Conclude that mango is the only common fruit in the list whose scientific name is Mangifera indica. Verification / Alternative check: Botany textbooks and horticultural guides list Mangifera indica as the primary mango species cultivated for fruit production. They describe the tree morphology, flowering and fruiting characteristics associated with mango orchards. Fruit industry reports and agricultural extension leaflets also use this scientific name when discussing mango varieties, diseases and cultivation practices. By contrast, descriptions of guava, amla and jack fruit always appear under different scientific names. This consistent usage confirms that Mangifera indica refers to the mango tree. Why Other Options Are Wrong: Option a, guava, has the scientific name Psidium guajava and thus does not match Mangifera indica. Option c, amla, is usually known as Phyllanthus emblica or Emblica officinalis, not Mangifera indica. Option d, jack fruit, is described botanically as Artocarpus heterophyllus, which is a different genus and species. Common Pitfalls: Students may mix up scientific names because they learn many at once and some names sound similar, especially when they all have an indica or officinalis component. Another issue is relying solely on regional names and not associating them properly with Latin binomials. To avoid these errors, it is helpful to memorise a short core list, such as Mangifera indica for mango, Psidium guajava for guava and Azadirachta indica for neem, and to recall them regularly when practising general science questions. Final Answer: Mangifera indica is the scientific name of the Mango tree.

Question 10

In international environmental law, there is a global agreement specifically designed to reduce and eventually phase out the production and consumption of chlorofluorocarbons (CFCs) and other ozone depleting substances. This agreement is known as wh…

Accepted Answer

Introduction / Context: Chlorofluorocarbons, commonly called CFCs, were once widely used in refrigeration, air conditioning and aerosol sprays. However, scientists discovered that these chemicals were damaging the ozone layer in the stratosphere, increasing harmful ultraviolet radiation reaching the Earth. In response, the international community negotiated a treaty to control and phase out ozone depleting substances. This question asks you to identify the name of that protocol from several similar sounding options. Given Data / Assumptions: CFCs are a major group of ozone depleting substances targeted by international regulation. A specific treaty was signed to reduce and eventually eliminate their production and consumption. The correct protocol name is widely known in environmental science and general knowledge. Other options such as CFC Protocol, IR Protocol and UV Protocol are not names of widely recognised international agreements. Concept / Approach: The Montreal Protocol on Substances that Deplete the Ozone Layer is the international treaty aimed at phasing out the production and use of CFCs and related ozone damaging chemicals. It was agreed in Montreal, Canada, and has been strengthened over time by amendments and adjustments. The protocol is considered one of the most successful environmental agreements, with significant recovery of the ozone layer expected because of it. Although the phrase CFC Protocol might sound descriptive, the official and universally recognised name is Montreal Protocol, not the generic terms given in other options. Step-by-Step Solution: Step 1: Recall that CFCs are linked to ozone layer depletion and that an international protocol was created to deal with this problem. Step 2: Remember the formal name Montreal Protocol on Substances that Deplete the Ozone Layer, usually shortened to Montreal Protocol. Step 3: Examine option c, Montreal Protocol, and recognise it as the correct official name of the treaty. Step 4: Consider option a, CFC Protocol, which is not the formal name even though it mentions CFCs. Step 5: Note that IR Protocol and UV Protocol in options b and d are not recognised names of global treaties, confirming that Montreal Protocol is the only accurate choice. Verification / Alternative check: Environmental policy documents and international law references describe the Montreal Protocol as a landmark treaty adopted in the late twentieth century and implemented under the framework of the Vienna Convention for the Protection of the Ozone Layer. They detail schedules for phasing out CFCs, halons and other ozone depleting substances, and highlight the positive impact on ozone recovery. No international agreement called CFC Protocol, IR Protocol or UV Protocol appears in this context. This confirms that Montreal Protocol is the correct name of the agreement aimed at reducing CFC production and usage. Why Other Options Are Wrong: Option a, CFC Protocol, might describe the focus of the treaty but is not its official or commonly used name. Option b, IR Protocol, suggests a connection with infrared radiation but does not correspond to any widely known environmental treaty controlling CFCs. Option d, UV Protocol, refers generically to ultraviolet radiation and is not the formal name of the agreement that actually regulates ozone depleting chemicals. Common Pitfalls: Because CFCs are directly associated with ozone depletion, some learners may be tempted by a name that explicitly mentions them, such as CFC Protocol, without recalling the proper historical and legal title. Others might confuse Montreal Protocol with different agreements on climate change or greenhouse gases. To avoid such confusion, it is helpful to remember a simple pairing: CFC control and ozone layer protection are linked with the Montreal Protocol, while climate change gas reductions are associated with other agreements such as the Kyoto Protocol and later frameworks. Final Answer: The protocol signed to reduce the production of CFCs is called the Montreal Protocol.

Question 11

In general science and chemistry, malachite is an important green coloured ore or mineral of which metal?

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Introduction / Context: Malachite is a well known green coloured mineral that students frequently encounter in general science, chemistry, and geology topics dealing with ores of metals. Examinations often test whether you can correctly link the name of a mineral to the metal it is an ore of. This question checks your recall of the fact that malachite is specifically an ore of copper, not of lead, mercury, or manganese. Knowing such associations helps in understanding metallurgical processes, mineral resources, and industrial uses of different metals. Given Data / Assumptions: – The mineral mentioned in the question is malachite, a green secondary mineral. – The task is to identify the metal for which malachite acts as an ore. – The options given are lead, copper, mercury, and manganese, all common industrial metals. – We assume standard school level general science and inorganic chemistry information about important metal ores. Concept / Approach: An ore is a naturally occurring mineral from which a metal can be extracted economically. Malachite is a copper carbonate hydroxide mineral with a characteristic bright green colour. It forms near the surface when primary copper sulphide minerals such as chalcopyrite are weathered. Because it contains a significant proportion of copper, malachite is considered an important ore of copper and is used as a source of this metal. Lead has ores such as galena, mercury has cinnabar, and manganese has ores like pyrolusite. None of these metals primarily rely on malachite as an ore in standard textbook lists, so copper is the correct match. Step-by-Step Solution: Step 1: Recall that malachite is a green carbonate mineral often mentioned together with copper minerals. Step 2: Remember that its chemical composition is a basic copper carbonate, which indicates a high copper content. Step 3: Compare this with common ores of other metals: galena for lead, cinnabar for mercury, and pyrolusite for manganese. Step 4: Conclude that malachite is specifically classified as an ore of copper and select copper as the correct option. Verification / Alternative check: If you look at a standard inorganic chemistry or earth science table of ores and metals, you will see malachite listed under the copper section, along with minerals like cuprite and chalcopyrite. These tables usually show the formula of malachite and explicitly identify it as a copper ore. By contrast, lists of lead, mercury, or manganese ores do not include malachite. This cross check with reliable reference data confirms that copper is indeed the metal associated with malachite as an ore. Why Other Options Are Wrong: Lead: The principal ore of lead is galena, a lead sulphide, not malachite, so this option does not match the known mineral metal pair. Mercury: Mercury is mainly obtained from cinnabar, a mercury sulphide ore; malachite is not used as an ore of mercury. Manganese: Manganese ores include minerals such as pyrolusite and psilomelane, which are manganese oxides, not copper carbonates like malachite. Common Pitfalls: A common mistake is to guess randomly among metals without recalling specific ore names. Some students may associate malachite only with its green colour and confuse it with decorative stones rather than treating it as a copper ore. Others might mix up different ore mineral names such as malachite, magnetite, and hematite. To avoid such errors, it helps to memorise short pairs like malachite copper, galena lead, cinnabar mercury, and bauxite aluminium. These simple associations make ore related questions easy scoring opportunities in competitive exams. Final Answer: Malachite is an important green coloured ore of the metal Copper.

Question 12

Which one of the following statements about planet Earth is false, when compared with the other planets of the solar system?

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Introduction / Context: Basic astronomy and general science questions frequently ask about key facts related to Earth and its position in the solar system. This question focuses on identifying which of several statements about Earth is false. To answer correctly, you need to know Earth's relative size, density, orbital position, and common nicknames used in astronomy. Recognising that the description red planet belongs to Mars rather than Earth is the key idea being tested here. Given Data / Assumptions: – The planet under discussion is Earth, our home planet. – Four statements are provided about Earth regarding density, size rank, nickname, and distance from the Sun. – Only one of these statements is false, while the others are essentially correct as per standard astronomy data. – We assume basic knowledge of the names and simple characteristics of planets in the solar system. Concept / Approach: Earth is the third planet from the Sun after Mercury and Venus. By volume and diameter, Earth is the fifth largest planet in the solar system, after Jupiter, Saturn, Uranus, and Neptune. Because it has a large iron core and a relatively compact structure, Earth is also the densest planet. However, the phrase red planet is firmly associated with Mars due to its reddish appearance caused by iron oxide on its surface. Earth is sometimes called the blue planet because of its abundant liquid water and cloud cover. Therefore, the statement that Earth is also known as the red planet is clearly false, while the other statements correctly describe important characteristics of Earth. Step-by-Step Solution: Step 1: Check the orbital position of Earth and confirm that it is the third planet from the Sun, which matches a true statement. Step 2: Recall that Earth is smaller than the four giant planets but larger than Mercury, Mars, and Venus, making it the fifth largest planet by size, which is also true. Step 3: Remember that Earth has a high average density and is listed as the densest planet in standard data tables, so that statement is correct. Step 4: Identify the nickname red planet as belonging to Mars, not Earth, which makes the statement calling Earth the red planet false. Verification / Alternative check: Astronomy reference books and educational posters commonly show Earth as the third planet from the Sun and label it as the blue planet. They rank planets by size and list Earth as the fifth largest. Data tables of mean density confirm that Earth has the highest average density among the planets. Mars is shown with a reddish surface and is labelled the red planet. These independent sources consistently assign the red planet nickname to Mars rather than to Earth, verifying that this is the incorrect statement in the question. Why Other Options Are Wrong (meaning not the false one): It is the densest planet in the solar system: This is essentially correct for Earth and therefore not the false statement being tested here. It is the fifth largest planet by size: This correctly describes Earth's size ranking and is not the incorrect option. It is the third planet from the Sun: This is a basic and accurate positional fact about Earth, so it is also not the false statement. Common Pitfalls: A common error is to answer too quickly and not notice that the question is specifically asking for the false statement. Some students also confuse nicknames and may loosely remember that some planet is called red without recalling that it is Mars. Others may be unsure about the exact size ranking of Earth and incorrectly doubt the correct statements. To avoid these mistakes, carefully read whether the question is asking for a true or false statement and firmly associate Mars with the red planet and Earth with the blue planet in your memory. Final Answer: The false statement about Earth is that it is also known as the red planet, because that description belongs to Mars, not to Earth.

Question 13

On which date is India, located in the Northern Hemisphere, most likely to experience the shortest day of the year?

Accepted Answer

Introduction / Context: Geography and earth science frequently test your understanding of solstices and equinoxes, which are key points in the annual movement of Earth around the Sun. In the Northern Hemisphere, one date corresponds to the winter solstice when the day is shortest and the night is longest. India lies entirely in the Northern Hemisphere, so the same seasonal pattern applies. This question asks you to recall which calendar date is associated with the shortest day in this hemisphere, a basic but important fact for understanding seasons and climate. Given Data / Assumptions: – The country mentioned is India, which is in the Northern Hemisphere. – The question refers to the shortest day of the year, which is the winter solstice for that hemisphere. – Options include four dates: December 22, March 21, June 22, and September 23. – We assume the approximate school level dates used for solstices and equinoxes, understanding that exact astronomical dates may shift by one day in some years. Concept / Approach: Because Earth's axis is tilted, the amount of sunlight received by different latitudes varies throughout the year. In the Northern Hemisphere, the winter solstice occurs when the North Pole tilts farthest away from the Sun, so the Sun's apparent path across the sky is at its lowest and shortest. This results in the shortest daylight period. This event happens around 21 or 22 December. In textbooks, this is usually given as 22 December for simplicity. March 21 and September 23 are approximate dates for the vernal and autumnal equinoxes, when day and night are nearly equal. June 22 is close to the summer solstice in the Northern Hemisphere, when the day is longest, not shortest. Therefore, December 22 is the correct answer for the shortest day in India. Step-by-Step Solution: Step 1: Identify that India is in the Northern Hemisphere, so the usual Northern Hemisphere seasonal dates apply. Step 2: Recall that the winter solstice, associated with the shortest day and longest night, occurs around 21 or 22 December. Step 3: Note that 21 March and 23 September are equinox dates, when day and night are almost equal in length. Step 4: Remember that 22 June is close to the summer solstice in the Northern Hemisphere, when the day is longest. Step 5: Conclude that December 22 is the date on which India is most likely to experience the shortest day. Verification / Alternative check: Standard school atlases and geography textbooks include diagrams showing the position of Earth on four key dates: around 21 March, 22 June, 23 September, and 22 December. These diagrams typically label 22 December as the winter solstice in the Northern Hemisphere and indicate that it has the shortest daylight duration there. Time charts for major cities in India also show the earliest sunset times and longest nights near this date. By cross checking these sources, you can confidently identify December 22 as the answer. Why Other Options Are Wrong: March 21: This date is associated with the spring equinox in the Northern Hemisphere, where day and night are nearly equal in length, not with the shortest day. June 22: This is close to the summer solstice, when the day is longest in the Northern Hemisphere, so it is essentially the opposite of what is asked. September 23: This is near the autumnal equinox, with approximately equal day and night, and does not represent the shortest day of the year. Common Pitfalls: Students often confuse solstices and equinoxes because all four key dates are in the early twenties of their respective months. It is easy to remember that 22 June is important and accidentally pick it as the shortest day without recalling that it is actually the longest day in the Northern Hemisphere. To avoid this, use a simple mental pattern: March and September for equal day and night, June for the longest day in the north, and December for the shortest day in the north. Associating these dates with basic seasonal imagery, such as winter nights in December, also helps reinforce the correct answer. Final Answer: India, being in the Northern Hemisphere, is most likely to experience its shortest day of the year on December 22.

Question 14

In meteorology, precipitation falling as a mixture of rain drops and snow particles together is called what?

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Introduction / Context: Weather and climate related questions often test your understanding of different forms of precipitation. While most people are familiar with rain and snow, there are several mixed or special forms such as sleet, hail, and drizzle. This question specifically asks about the name given to precipitation that consists of a mixture of rain and snow falling together. Correctly identifying sleet and distinguishing it from pure rain, snow, or hail is a common general science requirement. Given Data / Assumptions: – The question describes precipitation that is a mixture of rain and snow. – Four options are provided: hail, sleet, drizzle, and snow. – We assume standard meteorological definitions of these terms as taught in school geography and science. – The task is to pick the correct term that matches the described mixed precipitation type. Concept / Approach: Sleet refers to precipitation that consists of small ice pellets or a mix of partially melted snow and rain drops falling together, often during transitional temperatures near the freezing point. It commonly occurs when snowflakes partially melt as they fall through a layer of warmer air, then refreeze or remain mixed with liquid droplets by the time they reach the ground. Drizzle is very light liquid rain with tiny droplets. Hail consists of balls or lumps of ice formed in strong thunderstorm updrafts, usually in summer or spring storms. Snow is frozen precipitation that remains as ice crystals or flakes throughout its fall. Thus, among the options, sleet best matches the description of a mixture of rain and snow. Step-by-Step Solution: Step 1: Identify the key phrase in the question: a mixture of rain and snow falling together. Step 2: Recall that sleet is used to describe mixed or partially melted frozen precipitation, often appearing as ice pellets or a rain snow mix. Step 3: Note that drizzle is purely liquid rain in very small droplets, without snow. Step 4: Recognise that hail is made of larger ice balls formed in thunderclouds and is not simply a gentle mix of rain and snow. Step 5: Conclude that the correct term for mixed rain and snow precipitation is sleet. Verification / Alternative check: Meteorology glossaries and school textbooks on weather phenomena typically define sleet as precipitation composed of ice pellets or a mixture of rain drops and partially melted snow. Illustrations show sleet as falling in cold conditions near the freezing point, often leading to slippery roads. These same sources clearly distinguish drizzle as light rain, hail as large ice chunks from thunderstorms, and snow as full ice crystals. By comparing these definitions, you can confirm that only sleet fits the given description of a rain and snow mixture. Why Other Options Are Wrong: Hail: Hail consists of large, layered ice balls formed in intense thunderstorm updrafts, not the finer, mixed form of rain and snow described in the question. Drizzle: Drizzle is gentle, very light rain with tiny droplets and contains no snow component, so it cannot be the correct term here. Snow: Snow is completely frozen precipitation falling as ice crystals or flakes, without a liquid rain part, so it is not a mixture of rain and snow. Common Pitfalls: Some learners confuse sleet with hail, thinking that both are simply frozen precipitation. Others may incorrectly label any cold weather precipitation as snow even when rain drops are present. To avoid these mistakes, remember that hail is associated with severe thunderstorms and large ice balls, while sleet is a finer, often slushy mix associated with near freezing temperatures. Linking sleet to the idea of a rain and snow mixture or ice pellets will help you consistently recognise the correct term in exam questions. Final Answer: Precipitation that falls as a mixture of rain drops and snow together is called Sleet.

Question 15

When a fresh raw egg is gently placed in salt water of sufficiently high concentration, what will it do?

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Introduction / Context: This question illustrates an everyday application of the principle of density and buoyancy in liquids. Placing a fresh egg in plain water and then in salt water is a classic classroom demonstration used in school science experiments. The behaviour of the egg changes because the density of the surrounding liquid changes when salt is dissolved in water. Understanding why the egg floats in salt water helps reinforce the concept of relative density and Archimedes principle in a simple and memorable way. Given Data / Assumptions: – The egg mentioned is fresh and raw, not boiled or spoiled. – The water is salt water with enough dissolved salt to significantly increase its density. – The egg is placed gently into the solution, without external force pushing it down or stirring the water. – We assume normal conditions where the density of a fresh egg is slightly higher than pure water but lower than sufficiently concentrated salt water. Concept / Approach: Whether an object floats or sinks in a liquid depends on relative density. If the density of the object is greater than the density of the liquid, the object sinks. If the object is less dense than the liquid, it floats. A fresh egg usually has a density slightly greater than that of pure water, so it normally sinks in plain water. When salt is dissolved in water, the solution becomes denser because dissolved salt adds mass without proportionally increasing volume. If enough salt is added, the density of the salt water becomes higher than the density of the egg. In that case, the egg experiences a buoyant force greater than its weight and floats near the surface of the liquid. Step-by-Step Solution: Step 1: Recall that a fresh egg typically sinks in plain water because its density is slightly greater than that of pure water. Step 2: Understand that dissolving salt in water increases the density of the water, especially when the salt concentration is high. Step 3: Visualise that in sufficiently dense salt water, the egg now has a lower density than the surrounding liquid. Step 4: Apply the rule of buoyancy that objects less dense than the liquid float, and conclude that the egg will float near the surface. Verification / Alternative check: You can verify this behaviour through a simple home or classroom experiment. Place a fresh egg in a glass of plain water and observe that it sinks. Then gradually add salt, stirring gently until it fully dissolves, and watch how the egg rises and eventually floats near the surface. This direct observation confirms the theoretical explanation about density and buoyant force. It is the same principle that allows people to float more easily in the highly salty water of seas like the Dead Sea compared with normal lakes. Why Other Options Are Wrong: It will sink and go to the bottom of the container: This happens in plain water but not in sufficiently dense salt water, so it is not correct for the conditions described. It will sink but will not reach the bottom: In a typical demonstration, the egg either sinks completely in plain water or floats; the description of partial sinking is not the usual correct outcome for properly prepared salt water. It will burst open due to pressure: The pressure difference in a small glass of salt water is not enough to cause a fresh egg to burst, so this is incorrect. Common Pitfalls: Some students forget that the density of the liquid can be changed by dissolving substances and wrongly assume that the egg must always sink, regardless of salt concentration. Others may confuse the case of a spoiled egg, which sometimes floats in plain water due to internal gas formation, with this controlled density experiment. To avoid such confusion, focus on the idea that adding salt increases the density of the water and use the rule that objects float when they are less dense than the surrounding fluid. This reasoning leads you directly to the correct outcome that the egg will float in concentrated salt water. Final Answer: A fresh egg placed in sufficiently concentrated salt water will float near the surface of the salt water.

Question 16

Which of the following is least likely to be a direct effect of global warming on the Earth's climate and environment?

Accepted Answer

Introduction / Context: Global warming refers to the long term increase in Earth's average surface temperature mainly due to rising concentrations of greenhouse gases like carbon dioxide. This warming leads to a variety of climatic and environmental changes including altered weather patterns, sea level rise, and loss of ice. Many competitive exams ask you to distinguish between effects that are strongly supported by climate science and those that are less likely or more indirect. This question aims to test your understanding of which outcomes are typical and which are not strongly predicted as direct effects of global warming. Given Data / Assumptions: – The topic is global warming and its probable effects on the climate and environment. – Options mention changes in hurricanes, fertile delta regions, photosynthesis rates, and polar ice regions. – We assume standard climate science findings as summarised in widely accepted assessment reports. – The question is specifically asking for the least likely direct effect among the listed choices. Concept / Approach: Global warming is expected to intensify certain types of extreme weather events, including an increase in the frequency and intensity of some hurricanes and cyclones, particularly because warmer oceans provide more energy to storms. Rising temperatures also cause polar ice caps and glaciers to melt, contributing to sea level rise and the shrinking of polar ice regions. As sea levels rise, low lying coastal and delta regions face flooding and salinisation, leading to loss of fertile agricultural land. The effect of global warming on the overall rate of photosynthesis in vegetation is more complex. Higher levels of carbon dioxide can actually stimulate photosynthesis in many plants under favourable conditions, a phenomenon sometimes called carbon dioxide fertilisation. While heat stress and drought can harm plants in certain areas, a simple statement that global warming will cause a decreased overall rate of photosynthesis in vegetation is not a straightforward or universal prediction and is therefore the least likely direct effect as worded here. Step-by-Step Solution: Step 1: Identify which listed options are well known and widely accepted effects of global warming, such as increased storm intensity, sea level rise, and melting ice caps. Step 2: Recognise that increased frequency and intensity of hurricanes and shrinking polar ice regions are strongly supported by observational and modelling studies. Step 3: Understand that sea level rise threatens low lying deltas, leading to loss of fertile agricultural land as salt water inundates these areas. Step 4: Consider that photosynthesis in plants depends on temperature, water availability, and carbon dioxide concentration, and that elevated carbon dioxide can stimulate photosynthesis in many species. Step 5: Conclude that a simple blanket statement about decreased overall rate of photosynthesis in vegetation is less likely to be a direct and universal effect of global warming compared with the other options. Verification / Alternative check: Climate science summaries commonly list projected effects of global warming that include sea level rise, increased risk of heatwaves, changes in storm patterns, retreats of glaciers, and Arctic sea ice loss. Many reports discuss potential crop yield changes in a nuanced way, noting that higher carbon dioxide can promote photosynthesis but that heat stress, changing rainfall patterns, and extreme events can reduce yields in some regions. This complexity means that the direction of change in global photosynthesis is not simply described as a uniform decrease. In contrast, the association of warming with stronger storms, loss of fertile coastal regions due to sea level rise, and melting ice is much more straightforwardly accepted, supporting the idea that the photosynthesis statement is the least directly linked effect. Why Other Options Are Wrong (meaning they are more likely effects): Increased frequency and intensity of hurricanes and cyclones: Warmer sea surface temperatures can feed more intense storms, so this is a commonly cited likely effect of global warming. Loss of fertile delta regions due to sea level rise: Thermal expansion of water and melting ice raise sea levels, threatening low lying fertile deltas with flooding and salinisation, making this a realistic effect. Shrinking and melting of polar ice regions and glaciers: Observed warming has already led to reduced ice cover in polar regions and mountain glaciers, so this is a direct and well documented impact. Common Pitfalls: Students sometimes assume that any negative sounding environmental change must be a direct effect of global warming without considering the detailed scientific mechanisms. There is also a tendency to overlook the fact that carbon dioxide is a raw material for photosynthesis and can enhance plant growth under certain conditions. Another common mistake is to think that if climate change is harmful overall, every individual biological process must necessarily decrease. To avoid such oversimplifications, remember that global warming has a mix of direct and indirect effects, and not all of them point in the same direction for every process. In this question, comparing the clarity and strength of scientific evidence behind each option helps you identify that the statement about decreased overall photosynthesis is the least directly supported effect. Final Answer: The effect that is least likely to be a simple direct consequence of global warming, as worded, is Decreased overall rate of photosynthesis in most vegetation.

Question 17

To separate a dissolved solute from its liquid solution in a simple school laboratory, which process is most suitable?

Accepted Answer

Introduction / Context: In basic chemistry and general science, students learn different methods for separating mixtures based on the physical properties of their components. When a solid solute such as salt or sugar is dissolved in a liquid solvent like water, the resulting mixture is called a solution. This question asks which method is most suitable for separating the solute from the solution using simple equipment. Recognising when to use evaporation rather than sedimentation, filtration, or condensation is essential for understanding practical separation techniques. Given Data / Assumptions: – We have a solute that is completely dissolved in a liquid solvent, forming a homogeneous solution. – The goal is to recover the solute from the solution in a simple laboratory setting. – The options provided are sedimentation, evaporation, filtration, and condensation. – We assume the solute is non volatile compared with the solvent, as in the case of common salt dissolved in water. Concept / Approach: In a true solution, the particles of the solute are so small that they cannot be separated by ordinary mechanical methods like filtration or sedimentation. Filtration is suitable for suspensions where solid particles remain undissolved and can be trapped by a filter paper. Sedimentation and decantation are also used for such coarse solid liquid mixtures. Condensation is the process of converting vapour back into liquid and is part of distillation rather than a direct method to obtain solute from solution. Evaporation, on the other hand, involves heating the solution so that the liquid solvent gradually changes into vapour and escapes, leaving the solid solute behind. For common school experiments such as obtaining salt from salt water, evaporation is the most straightforward and correct process. Step-by-Step Solution: Step 1: Identify that the solute is completely dissolved in the solvent, forming a homogeneous solution with no visible solid particles. Step 2: Recognise that sedimentation and filtration are effective only when there are undissolved solid particles that can settle or be trapped. Step 3: Understand that condensation refers to cooling vapour to form liquid and does not by itself separate solute from solution. Step 4: Recall that evaporation removes the liquid component by converting it into vapour, leaving the non volatile solute behind. Step 5: Conclude that evaporation is the correct method to separate a dissolved solute from its solution in this context. Verification / Alternative check: School science textbooks commonly present an experiment in which salt water is placed in an evaporating dish and gently heated. As water evaporates, salt crystals remain as a solid residue. The same principle is used in salt pans where sea water is allowed to evaporate under the sun, leaving behind solid salt. These real world examples confirm that evaporation is the standard method for separating a non volatile solute from its solution when simple equipment is available. Filtration and sedimentation are always illustrated with muddy water or chalk water, not with clear solutions. Why Other Options Are Wrong: Sedimentation: This process involves heavier undissolved particles settling to the bottom of a container and does not work for true solutions where the solute is at the molecular level. Filtration: Filtration separates undissolved solids from liquids using filter paper or similar barriers, but dissolved solute particles pass through the filter with the solvent, so it cannot separate a true solution. Condensation: Condensation is the change of vapour to liquid and is only a part of distillation; by itself, it does not recover the solute from the original solution in a simple direct way. Common Pitfalls: A frequent mistake is to choose filtration simply because it is a widely known method for separating solids from liquids. Another is to mix up the terms evaporation and condensation, as both involve phase changes of the liquid. To avoid these errors, remember that if the solid is actually dissolved and you want the solid back, you typically allow the solvent to evaporate. Associating salt pans, where seawater evaporates leaving salt, with the term evaporation is a powerful memory aid for such questions. Final Answer: To separate a dissolved solute from its liquid solution using simple equipment, the most suitable process is Evaporation.

Question 18

In plant reproduction, pollination that is carried out by birds is technically known by which term?

Accepted Answer

Introduction / Context: Pollination is the transfer of pollen grains from the anther of a flower to the stigma of the same flower or another flower of the same species. Different agents such as wind, water, insects, and birds can carry out this transfer. Botany uses specific terms for pollination by different agents. This question tests whether you know the technical term used when birds act as the primary pollinating agents. Linking the correct term ornithophily with birds is a straightforward but important piece of vocabulary in plant pollination biology. Given Data / Assumptions: – The agent of pollination mentioned is birds. – Four terms are given as options: hydrophily, entomophily, ornithophily, and embryophily. – We assume school level knowledge of pollination and the naming pattern used for different pollinating agents. – The task is to select the term that specifically refers to bird pollination. Concept / Approach: Botanical terminology for pollination uses Greek or Latin roots that refer to the pollinating agent. Entomophily refers to insect pollination (entomon meaning insect). Hydrophily refers to pollination by water. Anemophily refers to pollination by wind, though this term does not appear among the options. Ornithophily is derived from ornithos, meaning bird, and phily meaning attraction or association. Thus, ornithophily literally means bird loving and describes pollination carried out by birds, especially nectar feeding species such as hummingbirds and sunbirds. Embryophily is not a standard term for pollination in basic botany textbooks and does not refer to any pollinating agent. Step-by-Step Solution: Step 1: Identify that the question clearly states that pollination is done by birds. Step 2: Recall the root ornitho, which is related to birds in many biological terms, such as ornithology, the study of birds. Step 3: Associate ornithophily with bird mediated pollination, based on this root. Step 4: Recognise that hydrophily refers to water based pollination and entomophily refers to insect based pollination. Step 5: Conclude that ornithophily is the correct term for pollination by birds. Verification / Alternative check: Botany textbooks that cover pollination syndromes often include a table listing anemophily, hydrophily, entomophily, chiropterophily, and ornithophily. The table explains that ornithophily involves pollination by birds and mentions characteristics of ornithophilous flowers, such as bright colours, tubular shapes, and abundant nectar, which attract birds. The same sources describe entomophily for insect pollination and hydrophily for pollination in aquatic environments through water. This consistent use of terminology confirms that ornithophily is the correct answer for bird based pollination. Why Other Options Are Wrong: Hydrophily: This term refers to pollination by water currents in aquatic plants and has no connection with birds as pollinators. Entomophily: This refers to pollination by insects such as bees, butterflies, and beetles, not by birds, so it does not match the given description. Embryophily: This is not a standard term used in common pollination classifications and does not describe any agent based pollination system in basic botany courses. Common Pitfalls: Students sometimes confuse ornithophily with entomophily because both words sound somewhat similar and both end with phily. Another common error is to guess hydrophily when they vaguely remember Greek roots but do not recall which root relates to which agent. To avoid such confusion, create mental links between the roots and their meanings: ornitho for birds, entomo for insects, hydro for water, and anemo for wind. These connections make it much easier to recall the correct terms when solving pollination questions in exams. Final Answer: Pollination that is carried out by birds is technically known as Ornithophily.

Question 19

In environmental science, who first coined the term “ecology” to describe the study of the relationships between organisms and their environment?

Accepted Answer

Introduction / Context: Ecology is a core branch of biology that focuses on the interactions between living organisms and their physical and biological environment. Understanding who coined the term provides historical context and often appears as a standard factual question in competitive exams. This question asks you to identify the scientist who first used the word ecology in a scientific sense. Recognising the contribution of Ernst Haeckel helps link the development of ecological thinking with the broader growth of evolutionary and environmental biology. Given Data / Assumptions: – The term in question is ecology, referring to the study of relationships between organisms and their surroundings. – Four scientists are listed: Ernst Haeckel, G. Evelyn Hutchinson, Hugo de Vries, and Robert Brown. – Only one of these scientists is historically credited with coining the word ecology. – We assume standard textbook level history of science concerning ecological terminology. Concept / Approach: The term ecology is derived from the Greek words oikos meaning house or environment and logos meaning study. Ernst Haeckel, a German biologist and strong supporter of Darwin's theory of evolution, introduced the term in the nineteenth century to describe the study of organisms in relation to both the biotic and abiotic components of their environment. G. Evelyn Hutchinson later became a prominent ecologist and contributed significantly to modern theoretical ecology but did not coin the word. Hugo de Vries is known for his work on mutation theory and genetics. Robert Brown is remembered for the discovery of Brownian motion and the nucleus in plant cells. Therefore, Ernst Haeckel is the correct answer to this question. Step-by-Step Solution: Step 1: Recall that ecology as a term comes from Greek roots meaning study of the environment. Step 2: Connect this term with the German biologist Ernst Haeckel, who formally introduced it in scientific literature. Step 3: Recognise that G. Evelyn Hutchinson is a major twentieth century ecologist but not the originator of the term. Step 4: Remember that Hugo de Vries is associated with mutation theory and plant genetics, not with coining ecology. Step 5: Note that Robert Brown is famous for Brownian motion and the cell nucleus, not for introducing ecological terminology. Verification / Alternative check: Biology and environmental science textbooks commonly state that the term ecology was coined by Ernst Haeckel in the nineteenth century. Historical summaries of ecology as a discipline mention Haeckel's definition of ecology as the study of the relationships of organisms to their environment. They also describe later contributions from scientists like Hutchinson, who elaborated on ecological niches and systems. This clear and consistent attribution in multiple sources confirms that Haeckel is the scientist who introduced the term. Why Other Options Are Wrong: G. Evelyn Hutchinson: He is regarded as a father of modern ecology and made major conceptual contributions, but he did not coin the term ecology itself. Hugo de Vries: Best known for mutation theory and rediscovery of Mendel's laws, he worked mainly in genetics and plant breeding rather than coining ecological terms. Robert Brown: Famous for describing Brownian motion and identifying the cell nucleus, he had no role in creating the term ecology. Common Pitfalls: Students sometimes confuse the scientist who coined a term with those who later developed the field. Because Hutchinson is heavily associated with ecology in modern texts, some learners mistakenly choose him instead of Haeckel. Others may not remember the historical context and simply guess among familiar names, especially if they have seen de Vries or Brown in other chapters. To avoid these errors, remember a simple fact: Ernst Haeckel introduced the word ecology, while later ecologists expanded and refined the discipline. Keeping this historical timeline in mind makes such questions straightforward. Final Answer: The term “ecology” for the study of relationships between organisms and their environment was coined by Ernst Haeckel.

Question 20

Silk worms used in sericulture mainly feed on the leaves of which one of the following plants?

Accepted Answer

Introduction / Context: Sericulture is the rearing of silk worms for the production of silk, an important cottage and commercial industry in many parts of the world, including India. Silk worms are very selective in their food habits and feed mainly on the leaves of a specific plant. This question checks whether you know that mulberry leaves are the primary food for the most commonly reared silk worm species. Understanding this basic fact helps connect biology with agricultural practices and rural livelihoods. Given Data / Assumptions: – The organism referred to is the silk worm used in sericulture, typically Bombyx mori. – The options include leaves of curry plant, mulberry plant, basil plant, and rose plant. – The question asks which plant provides the main food for silk worms. – We assume familiarity with simple facts about silk production taught in school biology and social science. Concept / Approach: The domesticated silk worm Bombyx mori feeds almost exclusively on mulberry leaves. Mulberry trees are therefore cultivated specifically to supply food for silk worm rearing. The quality and quantity of mulberry leaves directly affect the yield and quality of silk because the worms spin their cocoons from proteins synthesised using nutrients from these leaves. Curry leaves, basil, and rose plants are important for culinary, medicinal, or ornamental uses but are not used as primary feed for commercial silk worms. Consequently, mulberry plant leaves are the correct answer. Step-by-Step Solution: Step 1: Recall that sericulture involves raising silk worms in trays or rearing houses and feeding them carefully selected leaves. Step 2: Remember from school lessons that mulberry leaves are repeatedly mentioned as the preferred and almost exclusive food of Bombyx mori. Step 3: Recognise that curry leaves and basil are mainly used as spices in cooking, and rose plants are grown for flowers, not as silk worm feed. Step 4: Conclude that the plant on which silk worms feed in sericulture is the mulberry plant. Verification / Alternative check: Textbooks on biology and vocational subjects describe the stages of silk worm rearing, from egg to larva, pupa, and adult moth. In the larval stage, the worms are fed multiple times per day with fresh mulberry leaves. Photographs and diagrams in these books show trays of worms eating mulberry foliage. Agricultural extension materials for sericulture also emphasise the cultivation of mulberry trees as a key part of the industry. None of these sources recommend curry, basil, or rose as food plants for silk worms, confirming that mulberry leaves are the correct answer. Why Other Options Are Wrong: Curry leaves plant: These leaves are used in cooking to add flavour to dishes but are not the main food for silk worms in sericulture. Basil plant: Basil is an herb used for seasoning and medicinal purposes but does not serve as standard feed for silk worms. Rose plant: Roses are primarily grown for their flowers and are not suitable or commonly used as a food source for silk worms. Common Pitfalls: Some students may not remember the specific plant and may guess based on familiarity with common garden plants. Others may assume that any leafy plant could be suitable food. To avoid such mistakes, keep in mind the strong association between mulberry cultivation and silk production. When you think of silk worms, think of mulberry leaves; when you think of mulberry plantations, think of sericulture. This simple paired association ensures that you will select the correct option reliably in exams. Final Answer: Silk worms used in sericulture mainly feed on the leaves of the Mulberry plant.

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