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

The combustion of propane gas produces carbon dioxide and water vapor.
The combustion of propane gas produces carbon dioxide and what else?

The cytoskeleton holds cell organelles in place within the cytoplasm.
What part of the cell holds cell organelles in place within the cytoplasm?

Climate change theory theory helps predict future events in weather.
Which theory helps predict future events in weather?