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: Mammals can generate little bursts of energy by shivering. 
Question: What can a mammal produce by shivering?
Example Output: energy.

Example Input: Fact: Female mammals have breasts. 
Question: What has breasts?
Example Output: Female mammals.

Example Input: Fact: Aneurysms are caused by relaxation of cell walls of blood vessels. 
Question: What relaxes, thereby causing aneurysms?
Example Output:
blood vessels.