Fertilizers may wash into streams. Fertilizers may be used by weeds. Fertilizers may evaporate into the air. Fertilizers may come from natural materials.
I gave my students this multiple choice question: Most farmers use fertilizers on their cornfields. Which statement best explains why farmers should not use excess amounts of fertilizers?

Only one answer is correct among these 4 choices:
- Fertilizers may wash into streams.
- Fertilizers may be used by weeds.
- Fertilizers may evaporate into the air.
- Fertilizers may come from natural materials.

Could you tell me which one is correct?

Fertilizers may wash into streams.