Biological diversity. It studies all living organisms and how they interact with each other and their environment.
Answer:
I know you only need two, but here:
--Subsidence and sinkholes.
--Sinkholes and caverns.
--Waterfalls and rapids.
--Deltas and levees.
--Erosion and abrasion.
Explanation:
I believe your answer would be:
A. Fossils.
Explanation:
Because they are the preserved remains or traces of animals, plants, and other organisms from the past. They're also important evidence for evolution because they show that life on earth was once different from life found on earth today.
Hope I helped, good luck! =)
Deep ocean floor would be your answer :)
