Consumers at the lower level require more energy than the top-level consumers. Consumers at the top level require more energy than the lower-level consumers. The consumers are feeding on larger organisms that have less energy. The consumers are feeding on smaller organisms that have less energy.
I gave my students this multiple choice question: In a food pyramid, which best explains why the number of organisms decreases from one trophic level to the next?

Only one answer is correct among these 4 choices:
- Consumers at the lower level require more energy than the top-level consumers.
- Consumers at the top level require more energy than the lower-level consumers.
- The consumers are feeding on larger organisms that have less energy.
- The consumers are feeding on smaller organisms that have less energy.

Could you tell me which one is correct?

Consumers at the top level require more energy than the lower-level consumers.