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: an animal requires food to grow and heal. 
Question: What does an animal require food for?
[A]: to grow and heal.


[Q]: Fact: Water must not be polluted to be safe. 
Question: What can happen to water to make it unsafe?
[A]: Pollution.


[Q]: Fact: the movement of an air mass over the world's surface causes local weather changes. 
Question: What does the movement of air mass over the world's surface cause?
[A]:
local weather changes.