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.

Example Input: Fact: a flashlight requires a source of energy to produce light. 
Question: What requires a source of energy to produce light?
Example Output: flashlights.

Example Input: Fact: Exercise can teach animals how to behave. 
Question: What can teach animals how to behave?
Example Output: exercise.

Example Input: Fact: an animal requires heat produced by the body for survival. 
Question: an animal requires what by the body for survival?
Example Output:
heat produced.