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: if copper is exposed to a source of heat then that copper may easily become hot. 
Question: What can easily become hot if exposed to heat?

Output: copper.


Input: Consider Input: Fact: Aging is associated with apoptosis. 
Question: What stage is associated with apoptosis?

Output: aging.


Input: Consider Input: Fact: fluid in the inner ear is used for sensing sound by animals. 
Question: what in the inner ear is used for sensing sound by animals?


Output: fluid.