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.

Example Input: Fact: the stomach acidity helps digest fats. 
Question: What helps digest fats?
Example Output: stomach acidity.

Example Input: Fact: moist air falls on the windward side of a mountain. 
Question: Where does moist air fall on a mountain?
Example Output: windward side.

Example Input: Fact: The mass of the Earth helps cause flowing rivers. 
Question: Which aspect of the Earth is needed to have flowing rivers?
Example Output:
Mass.