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

[EX Q]: After fertilization, a zygote forms into two cells.
[EX A]: After fertilization, how many cells does a zygote form into?

[EX Q]: Volvox sphere has a distinct front and back end.
[EX A]: What has a distinct front and back end?

[EX Q]: After a massive eruption, a mountain collapsing above an empty chamber will create a caldera.
[EX A]:
After a massive eruption what will a mountain collapsing above an empty chamber create?