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

[Q]: A change of season and less food usually cause certain animals to migrate.
[A]: Which two environmental changes usually cause certain animals to migrate?

[Q]: Muscle groups are controlled by the motor cortex .
[A]: Muscle groups are controlled by what mechanism?

[Q]: Horse of these most likely has the greatest mass.
[A]:
Which of these most likely has the GREATEST mass?