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

[Q]: Oxygen gas is given off by plants.
[A]: Which gas is given off by plants?

[Q]: Aerobic exercise helps improve the cardiovascular system, while anaerobic exercise causes muscles to get bigger and stronger.
[A]: Aerobic exercise helps improve the cardiovascular system, while what exercise causes muscles to get bigger and stronger?

[Q]: Carnivores is the term for heterotrophs that eat only or mainly animals.
[A]:
What is the term for heterotrophs that eat only or mainly animals?