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: mammals keep warm with hair. 
Question: what do mammals keep warm with?
Example Output: hair.

Example Input: Fact: conserving water can be used for survival in a desert. 
Question: Where is conserving water useful for survival?
Example Output: desert.

Example Input: Fact: if copper is exposed to a source of heat then it may become hot. 
Question: What material will become hot if exposed to a heat source?
Example Output:
Copper.