Turn the given fact into a question by a simple rearrangement of words. This typically involves replacing some part of the given fact with a WH word. For example, replacing the subject of the provided fact with the word "what" can form a valid question. Don't be creative! You just need to rearrange the words to turn the fact into a question - easy! Don't just randomly remove a word from the given fact to form a question. Remember that your question must evaluate scientific understanding. Pick a word or a phrase in the given fact to be the correct answer, then make the rest of the question. You can also form a question without any WH words. For example, "A radio converts electricity into?"

Q: Fact: digestive systems are needed to keep cells alive.

A: What do cells need to keep them alive?
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Q: Fact: A chemical reaction involving rapid oxidation converts chemical energy into light and heat energy.

A: A chemical reaction involving what converts chemical energy into light and heat energy?
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Q: Fact: A barometer is used to measure the force acting on a unit area.

A:
What is used to measure the force acting on a unit area?
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