instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
A penguin must do increase muscle mass before molting.
answer:
A penguin must do what before molting?


question:
A(n) gastropods is noted for having its eyes at the tips of stalks or tentacles that emerge from its head.
answer:
What type of creature is noted for having its eyes at the tips of stalks or tentacles that emerge from its head?


question:
There have been five major massive extinctions since life began on earth.
answer:

How many major massive extinctions have been since life began on earth?