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

Input: Consider Input: A crater can usually be found on the top of composite volcanoes.

Output: A crater can usually be found on the top of what kind of volcanoes?


Input: Consider Input: A penguin must do increase muscle mass before molting.

Output: A penguin must do what before molting?


Input: Consider Input: The difference in electric potential energy which allows for an electric charge to move from one position to another is measured by the volt si unit.


Output: The difference in electric potential energy which allows for an electric charge to move from one position to another is measured by what si unit?