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.
--------
Question: Fact: Some parasites survive on the surface of their host. 
Question: Where so parasites go to survive?

Answer: on a host.


Question: Fact: Repellents can stop harm caused by flea bites. 
Question: How can you prevent harm caused by flea bites?

Answer: Using repellent.


Question: Fact: Any surface that has not been cleaned is likely to be covered with bacteria. 
Question: What should you do to a surface to make sure it doesn't have bacteria on it?

Answer:
clean it.