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

Example Input: A(n) an ionic bond forms when the metal sodium gives up an electron to the nonmetal chlorine.
Example Output: What forms when the metal sodium gives up an electron to the nonmetal chlorine?

Example Input: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.
Example Output: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?

Example Input: Ice masses, acquifers, and the deep ocean are examples of water reservoirs.
Example Output:
Ice masses, acquifers, and the deep ocean are examples of water what?