The bacteria break down water into food. The bacteria change sunlight into minerals. The bacteria combine with sand to form rocks. The bacteria break down plant and animal matter.
I gave my students this multiple choice question: Many bacteria are decomposer organisms. Which of the following statements best describes how these bacteria help make soil more fertile?

Only one answer is correct among these 4 choices:
- The bacteria break down water into food.
- The bacteria change sunlight into minerals.
- The bacteria combine with sand to form rocks.
- The bacteria break down plant and animal matter.

Could you tell me which one is correct?

The bacteria break down plant and animal matter.