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: Viruses are viewed by illuminating electrons. 
Question: What of the following can only be viewed by illuminating electrons?
Example Output: viruses.

Example Input: Fact: a drug that can be addictive is an example of a psychoactive drug. 
Question: a drug that can be addictive is an example of a what?
Example Output: psychoactive drug.

Example Input: Fact: pulped wood requires cutting down trees. 
Question: what requires cutting down trees?
Example Output:
pulped wood.