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: waves can be used to produce electricity. 
Question: What can be used to produce electricity?
answer:
waves.


question:
Fact: when the season changes  the amount of hours will change. 
Question: What happens when the season changes?
answer:
the amount of hours changes.


question:
Fact: abalone have a circulatory system with one or two hearts that pump blood. 
Question: What has a circulatory system with one or two hearts that pump blood?
answer:

abalone.