Given a scientific question, generate a correct answer to it.

Input: Consider Input: Ocean ridges formed by marine invertebrates living in warm shallow waters within the photic zone of the ocean are called what?

Output: coral reefs

Input: Consider Input: The pelvic girdle, consisting of a hip bone, serves to attach a lower limb to this?

Output: axial skeleton

Input: Consider Input: Where do the steps in the water cycle begin?
Output: the ocean