You will be given a definition of a task first, then some input of the task.
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Ocean ridges formed by marine invertebrates living in warm shallow waters within the photic zone of the ocean are called coral reefs.
Output:
Ocean ridges formed by marine invertebrates living in warm shallow waters within the photic zone of the ocean are called what?