changing environments. volcanic activity. changing rates of erosion. evaporation of sea water.
I gave my students this multiple choice question: Two layers of sedimentary rock are exposed on the side of a hill. Only one of the layers has fossils. The lack of fossils in one layer of sedimentary rock is most likely due to

Only one answer is correct among these 4 choices:
- changing environments.
- volcanic activity.
- changing rates of erosion.
- evaporation of sea water.

Could you tell me which one is correct?

changing environments.