Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Cancer occurs most often in adults over fifty age.
Cancer occurs most often in adults over what age?

Hydras and sea anemones are examples of apolyp.
Hydras and sea anemones are examples of what form?

The vertebrate endoskeleton can also be called a(n) internal skeleton.

The vertebrate endoskeleton can also be called what?