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: A bill is used for catching prey by some birds. 
Question: What is used by some birds to catch their prey?
[EX A]: a bill.

[EX Q]: Fact: The things that are the smallest agents of disease are usually considered to be nonliving. 
Question: The things that are the smallest agents of disease are usually considered to be what?
[EX A]: nonliving.

[EX Q]: Fact: sinkholes can be formed by snow. 
Question: Sinkholes can be formed by?
[EX A]:
snow.