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

[EX Q]: Human facial expressions can communicate emotions.
[EX A]: What can human facial expressions communicate?

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

[EX Q]: Combustion reaction occurs when a substance reacts quickly with oxygen.
[EX A]:
What occurs when a substance reacts quickly with oxygen?