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.

[Q]: Fact: Aging is associated with apoptosis. 
Question: What stage is associated with apoptosis?
[A]: aging.


[Q]: Fact: living things all require energy conservation as a trait. 
Question: living things all require energy conservation as a what?
[A]: trait.


[Q]: Fact: Nitrogen is found in most molecules. 
Question: _ is found in most molecules.?
[A]:
Nitrogen.