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

[Q]: If two populations do not mate and produce fertile offspring, separate species result.
[A]: If two populations do not mate and produce fertile offspring, what results?


[Q]: A moose eats a plant is an example of a living thing that depends on another living thing to survive.
[A]: Which statement best identifies a living thing that depends on another living thing to survive?


[Q]: The pion can only be created by violating the conservation of mass-energy.
[A]:
The pion can only be created by violating the conservation of what?