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.

Input: Consider Input: Fact: be prepared for clear, cold days after thunderstorms. 
Question: be prepared for clear, cold days after what?

Output: thunderstorms.


Input: Consider Input: Fact: Passenger pigeons could not produce enough offspring. 
Question: What could not produce enough offspring?

Output: passenger pigeons.


Input: Consider Input: Fact: Ethologists usually study how animals use instincts in their natural environment. 
Question: Ethologists study how animals use what in their natural environment?


Output: instincts.