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: 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?

Output: bone marrow.


Input: Consider Input: Fact: Light enters the eye through an opening that is reactive to light and accomodation. 
Question: Light enters the eye through an opening that is what to light and accommodation?

Output: reactive.


Input: Consider Input: Fact: cooking an egg causes a chemical reaction in the egg. 
Question: What causes a chemical reaction in an egg?


Output: cooking.