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: an automobile engine transforms chemical energy into sound. 
Question: an automobile engine cn transforms chemical energy into?
Example Output: sound.

Example Input: Fact: a polar bear requires extremely low humidity. 
Question: what does a polar bear require?
Example Output: extremely low humidity.

Example Input: Fact: The key cells involved in the immune response produce antibodies. 
Question: The cells that produce antibodies are key in what system?
Example Output:
immune.