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: Complex chemistry occurs in cells. 
Question: What occurs in cells?
[A]: complex chemistry.


[Q]: Fact: conserving water can be used for survival in a desert. 
Question: Where is conserving water useful for survival?
[A]: desert.


[Q]: Fact: Clean power is sometimes used for heating buildings. 
Question: What is sometimes used for heating buildings?
[A]:
clean power.