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: be prepared for clear, cold days after thunderstorms. 
Question: be prepared for clear, cold days after what?
[A]: thunderstorms.


[Q]: Fact: fields make compasses point north. 
Question: What makes compasses point north?
[A]: fields.


[Q]: Fact: riding a bike does not spoil the environment. 
Question: What does not spoil the environment?
[A]:
Riding a bike.