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.

[EX Q]: Fact: Distilling water removes harmful substances before drinking. 
Question: Distilling water removes what before people drink it?
[EX A]: harmful substances.

[EX Q]: Fact: The pituitary gland regulates the metabolic rate in the body. 
Question: What gland helps regulate the metabolic rate in the body?
[EX A]: Pituitary gland.

[EX Q]: Fact: the emission of sulfur dioxide causes soil weathering. 
Question: Emission of what gas causes soil weathering?
[EX A]:
Sulfur dioxide.