Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: The energy stored in the organic molecules of food ultimately comes from the sun.

Answer: The energy stored in the organic molecules of food ultimately comes from where?

Question: Renewable energy sources emit fewer or no greenhouse gases.

Answer: What type energy sources emit fewer or no greenhouse gases?

Question: The mole fraction of the solvent is just one minus the mole fraction of solute.

Answer:
The mole fraction of the solvent is just one minus the mole fraction of what?