Plants are described as photosynthetic autotrophs. What does this term mean about how they obtain their food and energy?

Introduction / Context:
In biology, organisms are often classified according to how they obtain energy and food. The term photosynthetic autotroph is used frequently in textbooks to describe plants and some microorganisms. This question checks whether you understand what that term implies about the nutrition of plants.

Given Data / Assumptions:

• The phrase has two parts: photosynthetic and autotroph.
• Photosynthetic relates to using light energy.
• Autotroph means self feeding or self nourishing.
• The options distinguish between making food and obtaining it from other organisms.

Concept / Approach:
An autotroph is an organism that can produce its own organic food from inorganic substances, rather than relying on other organisms as a food source. Photosynthetic autotrophs specifically use light energy, usually from the Sun, to drive the chemical reactions of photosynthesis. Plants take in carbon dioxide from the air and water from the soil, and using light energy in chloroplasts, they produce glucose and other organic compounds. Therefore, the correct answer is that they make their own food using light, carbon dioxide, and water, not that they feed on other organisms or live as parasites.

Step-by-Step Solution:

Verification / Alternative check:
Textbooks define plants as photosynthetic autotrophs and contrast them with animals, which are heterotrophs. Diagrams of energy flow in ecosystems show energy moving from sunlight to producers (plants) through photosynthesis, and then to consumers (animals) through feeding. These diagrams highlight that plants are the primary producers, making their own food and supporting the rest of the food chain, which confirms the chosen interpretation.

Why Other Options Are Wrong:

• Feeding on other organisms describes heterotrophs, not autotrophs.
• Depending only on stored seed food is wrong because plants actively photosynthesise and make new food once they emerge from seeds.
• Living as parasites on animals describes parasitic plants or organisms, not the typical nutrition of green plants.

Common Pitfalls:
Some learners may mix up autotroph and heterotroph or think that all plants behave the same, including parasitic species. While some special plants are parasitic, the general rule is that green plants with chlorophyll are photosynthetic autotrophs. Remember that auto means self and photo means light to keep the concept clear.

Final Answer:
They make their own organic food using light energy, carbon dioxide, and water