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]: Sporopollenin protects the pollen of seed plants and spores of seedless plants.
[A]: What protects the pollen of seed plants and spores of seedless plants?


[Q]: Mass matter reacts, there can be what that comes from nowhere and is unaccounted for.
[A]:
When matter reacts, there can be what that comes from nowhere and is unaccounted for?