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

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


[Q]: All metabolic functions carried out by a prokaryote take place in the plasma membrane or cytosol else.
[A]: All metabolic functions carried out by a prokaryote take place in the plasma membrane or where else?


[Q]: A shallow area of sediment near the shore best describes the part of the ocean called the continental shelf.
[A]:
Which best describes the part of the ocean called the continental shelf?