What process is responsible for building successive rock layers on earth?
deposition

faulting

folding

erosion

What do heterotrophic cells need to survive?

Suppose you are estimating the size of a blue crab population. what is the population size if the number marked in the first catch is 40, the total number in the second catch is 200, and the number marked in the second catch is 50?

Apaleontologist finds a plant fossil that shows that the plant had seeds. what can the paleontologist conclude?