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

[EX Q]: Solid form do alkali metals take at room temperature.
[EX A]: What form do alkali metals take at room temperature?

[EX Q]: Line graphs are especially useful for showing changes over time.
[EX A]: Line graphs are especially useful for showing changes over what?

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