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

[Q]: Instead of heat, organisms use catalysis to speed up reactions.
[A]: Instead of heat, organisms use what to speed up reactions?


[Q]: Light retains its original color under water because frequency remains the same when light is refracted.
[A]: Light retains its original color under water because what remains the same when light is refracted?


[Q]: A metal rod of these transmits sound the fastest.
[A]:
Which of these transmits sound the fastest?