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: mammals are endothermic. 
Question: what are endothermic?

Output: mammals.


Input: Consider Input: Fact: Dilation occurs when cell walls ease up. 
Question: What occurs when cell walls ease up?

Output: dilation.


Input: Consider Input: Fact: heat energy falls from the equator to the poles. 
Question: what falls from the equator to the poles?


Output: heat energy.