wind and rain. animal movement. crops grown in the soil. increased temperatures.
I gave my students this multiple choice question: The prairie grass ecosystem once had a deep layer of topsoil which was protected by the grasses that covered it. Removal of these grasses for farmland is causing the soil to be eroded mainly by

Only one answer is correct among these 4 choices:
- wind and rain.
- animal movement.
- crops grown in the soil.
- increased temperatures.

Could you tell me which one is correct?

wind and rain.