coral reef high desert oceanic trench evergreen forest
I gave my students this multiple choice question: Producers can use photosynthesis to capture energy for food webs in most ecosystems. In which ecosystem must producers capture energy from gases such as methane and hydrogen sulfide?

Only one answer is correct among these 4 choices:
- coral reef
- high desert
- oceanic trench
- evergreen forest

Could you tell me which one is correct?

oceanic trench