It was once a hot desert. It was once a shallow sea. It was once part of a glacier. It was once part of a rain forest.
I gave my students this multiple choice question: Students on a field trip discovered fossilized shark teeth on the side of a cliff. Which conclusion can best be made about the history of the area?

Only one answer is correct among these 4 choices:
- It was once a hot desert.
- It was once a shallow sea.
- It was once part of a glacier.
- It was once part of a rain forest.

Could you tell me which one is correct?

It was once a shallow sea.