Read the passage carefully and then choose the best answer to each question out of the four alternatives. Manja, the glass coated string used for flying kites, poses a threat not only to humans, animals and birds but also to trees. A study by the oldest botanical garden in the country has revealed that it poses a serious danger to trees. A research paper from the Acharya Jagdish Chandra Bose Indian Botanic Garden, in Howrah district of West Bengal, explains in detail how manja and climbers together damage trees. Question: How many scientists contributed to the study on how manja can kill a tree?

Introduction / Context:
This is a factual detail question from the same passage about environmental damage caused by manja, the glass coated kite string. Instead of asking about general concepts, the question focuses on a specific numeric fact: the number of scientists involved in the study that documented how manja can kill trees. Such questions test accurate reading and memory of exact figures mentioned in the passage.

Given Data / Assumptions:

• The passage mentions a research paper from Acharya Jagdish Chandra Bose Indian Botanic Garden.
• It explicitly states how many scientists authored or contributed to that paper.
• The question asks: How many scientists contributed to the study on how manja can kill a tree.
• Options: Two, Three, Five, Four.

Concept / Approach:
Since the question asks for a direct factual detail, no interpretation or inference is required. The correct approach is to recall or quickly locate the sentence in the passage that specifies the number of scientists and then match that number with the options. This is an example of a detail based comprehension question, where careful attention to numeric information is key.

Step-by-Step Solution:
Step 1: Remember the exact line from the passage that talks about the research paper.Step 2: The passage states that a research paper by three scientists of the Acharya Jagdish Chandra Bose Indian Botanic Garden describes how manja and climbers damage trees.Step 3: Focus on the phrase by three scientists, which clearly gives the number of contributors.Step 4: Compare this number with the options given: Two, Three, Five, Four.Step 5: Select Three as the correct answer.

Verification / Alternative check:
To verify, mentally reconstruct the relevant sentence: A research paper by three scientists of the Acharya Jagdish Chandra Bose Indian Botanic Garden illustrates in detail how the manja, in collusion with climbers, does the damage. The number three is directly mentioned and is not implied or estimated. None of the other numbers appear anywhere in that part of the passage. This confirms that the correct choice is Three.

Why Other Options Are Wrong:
Two: The passage never mentions two scientists; this is a distractor for candidates who misremember or guess. Five: This number also does not appear and would likely correspond to a larger research team than described. Four: Again, the passage specifies three scientists, not four, so this option is incorrect. Any answer other than three would contradict the explicit information given in the passage.

Common Pitfalls:
In detail oriented questions, candidates sometimes skim passages too quickly and later confuse numbers like three and four. Another pitfall is relying on general knowledge, such as a belief that most research papers are written by multiple scientists, and then guessing a larger number without checking the text. A reliable strategy is to underline or mentally note all numbers and dates while reading, so that such specific questions can be answered confidently without confusion.

Final Answer:
The study on how manja can kill a tree was conducted by three scientists.