Given a fact, create a question that can be answered using the fact. Construct the question such that it is unambiguous, has a unique answer and the answer can be given using the fact.

Q: Fact: a cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone

A: Kool-aid is a mix of what items as a solution?
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Q: Fact: the lunar surface contains many craters

A: The biggest things on the moon are?
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Q: Fact: a solution is made of one substance dissolved in another substance

A:
Jerry put some salt into some tap water and stirred it up. What has Jerry made?
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