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.

Input: Consider Input: Fact: cell regeneration requires rest. 
Question: what requires rest?

Output: cell regeneration.


Input: Consider Input: Fact: Force being exerted on a soccer ball compresses it. 
Question: Force being exerted on a soccer ball does what?

Output: compresses it.


Input: Consider Input: Fact: mutualism exists between dogs and humans. 
Question: what exists between dogs and humans?


Output: mutualism.