Rocks form deep underground. Rocks become smooth and round. Rocks are broken apart into small pieces. Rocks are moved from one place to another.
I gave my students this multiple choice question: Erosion and weathering can both cause changes to the surface of Earth. Which of the following happens only because of erosion and NOT because of weathering?

Only one answer is correct among these 4 choices:
- Rocks form deep underground.
- Rocks become smooth and round.
- Rocks are broken apart into small pieces.
- Rocks are moved from one place to another.

Could you tell me which one is correct?

Rocks are moved from one place to another.