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

Q: You see a faster reaction rate when the concentration of reactants is higher.

A: What kind of reaction do you see when the concentration of reactants is higher?
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Q: Potential energy type of energy is possessed by autumn leaves before they fall.

A: What type of energy is possessed by autumn leaves before they fall?
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Q: Two membranes form the mitochondrion structure of a cell.

A:
How many membranes form the mitochondrion structure of a cell?
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