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

[EX Q]: The size and symmetry of a beetle’s or an elk’s antlers or a grasshopper’s song communicate rather clearly their state of health.
[EX A]: The size and symmetry of a beetle’s or an elk’s antlers or a grasshopper’s song communicate rather clearly their state of what?

[EX Q]: Compression zones is the opposite of rarefaction zones, where air molecules in waves are loosely packed.
[EX A]: What is the opposite of rarefaction zones, where air molecules in waves are loosely packed?

[EX Q]: 300 million years long ago did the ancestors of mammals evolve.
[EX A]:
How long ago did the ancestors of mammals evolve?