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: Light enters the eye through an opening that is reactive to light and accomodation. 
Question: Light enters the eye through an opening that is what to light and accommodation?

A: reactive.
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Q: Fact: erosion forms canyons. 
Question: What are formed by erosion?

A: canyons.
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Q: Fact: streams join rivers. 
Question: What joins rivers?

A:
streams.
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