How long will the dirt stay wet? What types of animals live in the dirt? Will adding more water change the type of dirt? Do different types of dirt wash away at different rates?
I gave my students this multiple choice question: Sam poured water on a pile of dirt and observed that some dirt eroded from the pile. Which question could he test to learn more about erosion?

Only one answer is correct among these 4 choices:
- How long will the dirt stay wet?
- What types of animals live in the dirt?
- Will adding more water change the type of dirt?
- Do different types of dirt wash away at different rates?

Could you tell me which one is correct?

Do different types of dirt wash away at different rates?