Nutrients are released into the soil. Soil erosion decreases. Carbon dioxide is absorbed by the soil. Soil temperature decreases.
I gave my students this multiple choice question: How does an ecosystem benefit when leaves fall from a tree and decompose on the soil?

Only one answer is correct among these 4 choices:
- Nutrients are released into the soil.
- Soil erosion decreases.
- Carbon dioxide is absorbed by the soil.
- Soil temperature decreases.

Could you tell me which one is correct?

Nutrients are released into the soil.