Which of the following can be inferred from paragraph 2 as the reason that the origin of atolls has generated more interest than has the origin of other types of reefs? A. Most reefs have a predictable shape, but atolls do not. B. Atolls appear to form more rapidly than other kinds of reefs. C. The animals that form coral reefs cannot live in water below 70 meters, but atolls only form in very deep water. D. Atolls have more diverse origins and histories than other types of reefs.