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.
--------
Question: Fact: living things all require energy conservation as a trait. 
Question: living things all require energy conservation as a what?

Answer: trait.


Question: Fact: most bigger cities require vehicles. 
Question: What do most bigger cities require?

Answer: vehicles.


Question: Fact: a calculator is used for subtracting. 
Question: What is used for subtracting?

Answer:
a calculator.