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

[EX Q]: The combustion of propane gas produces carbon dioxide and water vapor.
[EX A]: The combustion of propane gas produces carbon dioxide and what else?

[EX Q]: Hybridization model model helps explain molecules with double or triple bonds.
[EX A]: Which model helps explain molecules with double or triple bonds?

[EX Q]: The turning driveshaft causes the wheels of the car to turn.
[EX A]:
What causes the wheels of the car to turn?