crustal deformation frequent earthquakes glacial movement volcanic eruptions
I gave my students this multiple choice question: When bedrock in Massachusetts is examined, it often appears scraped and polished. Which of the following most likely caused the bedrock to appear scraped and polished?

Only one answer is correct among these 4 choices:
- crustal deformation
- frequent earthquakes
- glacial movement
- volcanic eruptions

Could you tell me which one is correct?

glacial movement