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

[EX Q]: Gabbro is a dark dense rock that can be found in the oceanic crust.
[EX A]: Gabbro is a dark dense rock that can be found in what?

[EX Q]: Some compounds form rigid frameworks called crystals.
[EX A]: Some compounds form rigid frameworks called what?

[EX Q]: Urea and carbon dioxide are molecules with one many carbon atoms.
[EX A]:
Urea and carbon dioxide are molecules with how many carbon atoms?