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: the functions of life require energy. 
Question: What is energy required for?

Answer: The functions of life.


Question: Fact: cell division is how humans grow and repair themselves. 
Question: what uses cell division to grow and repair themselves?

Answer: humans.


Question: Fact: water vapor sometimes falls as rain. 
Question: What sometimes falls as rain?

Answer:
Water vapor.