instruction:
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: Repellents can stop harm caused by flea bites. 
Question: How can you prevent harm caused by flea bites?
answer:
Using repellent.


question:
Fact: locusts spread disease and destroy crops. 
Question: What spreads disease and destroy crops?
answer:
locusts.


question:
Fact: Sperm and egg nuclei combine to fertilize gametes. 
Question: Sperm and egg nuclei combine to do what?
answer:

fertilize gametes.