It was once underwater. It was once much warmer. It has become a rockier place. It has changed little from then.
I gave my students this multiple choice question: Fossils of sea animals were found in a cave in Arkansas. What does this mean about that area of Arkansas in the past?

Only one answer is correct among these 4 choices:
- It was once underwater.
- It was once much warmer.
- It has become a rockier place.
- It has changed little from then.

Could you tell me which one is correct?

It was once underwater.