coral reefs that slowly changed size desert sand dunes that were shaped by winds deposits of sediment found at the mouth of a river rock containing fossilized seashells found on a mountaintop
I gave my students this multiple choice question: Which of the following provides the best evidence that Earth has evolved over geologic time?

Only one answer is correct among these 4 choices:
- coral reefs that slowly changed size
- desert sand dunes that were shaped by winds
- deposits of sediment found at the mouth of a river
- rock containing fossilized seashells found on a mountaintop

Could you tell me which one is correct?

rock containing fossilized seashells found on a mountaintop