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

[Q]: The water in some springs are hot because they're heated by hot magma.
[A]: The water in some springs are hot because they're heated by what?

[Q]: Prostate is the most common type of cancer in adult males.
[A]: What is the most common type of cancer in adult males?

[Q]: There have been five major massive extinctions since life began on earth.
[A]:
How many major massive extinctions have been since life began on earth?