Write a correct answer to the given question based on its associated fact. Make sure that your answer is contained in the associated fact. Don't be creative and introduce any new word that is not mentioned in the associated fact! Remember that the associated fact has been rearranged to form the question. So, the correct answer words must lie within the associated fact. The correct answer can be a word, phrase, or even a sentence.

Q: Fact: Complex chemistry occurs in cells. 
Question: What occurs in cells?

A: complex chemistry.
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Q: Fact: Stimuli can cause the brain to experience pain. 
Question: What can cause the brain to experience pain?

A: stimuli.
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Q: Fact: cells cannot survive without plants replenishing the atmosphere. 
Question: cells cannot survive without plants replenishing the what?

A:
atmosphere.
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