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: the key cells involved in the immune response are produced in the bone marrow. 
Question: where are the key cells involved in the immune response produced in?
Example Output: bone marrow.

Example Input: Fact: if copper is exposed to a source of heat then that copper may easily become hot. 
Question: What can easily become hot if exposed to heat?
Example Output: copper.

Example Input: Fact: braking causes the temperature of an object to increase. 
Question: Braking would cause what to an object's temperature?
Example Output:
it would increase.