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: Lung cancer is most often caused by exposure to cigarettes. 
Question: What is lung cancer most often caused by exposure to?

Output: cigarettes.


Input: Consider Input: Fact: Protective equipment is used for protecting the eyes during experiements. 
Question: What is used for protecting the eyes during experiements?

Output: protective equipment.


Input: Consider Input: Fact: Opportunistic infections may be a result of an infection or injury of the lungs. 
Question: After an infection or injury to the lung, what can happen?


Output: opportunistic infections.