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: A protein-rich fluid leaks into spaces between cells. 
Question: A protein-rich what leaks into spaces between cells?
Example Output: fluid.

Example Input: Fact: Plants respond to green manures to disrupt plant disease. 
Question: Plants respond to what to disrupt plant disease?
Example Output: green manures.

Example Input: Fact: Nuclear fission can be used to heat buildings. 
Question: Which of the following is sometimes  used to indirectly heat buildings?
Example Output:
nuclear fission.