You are presented with the quiz "What being found in a place shows that place used to be covered by water?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past" and "fossils are the remains of prehistoric life". 

So, what's the best answer to the question?


 

        remains of prehistoric life   