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.

[EX Q]: Fact: be prepared for clear, cold days after thunderstorms. 
Question: be prepared for clear, cold days after what?
[EX A]: thunderstorms.

[EX Q]: Fact: The eye is an organ that can sense photons. 
Question: What does the organ of the eye sense?
[EX A]: Photons.

[EX Q]: Fact: Ancestors of hagfish are thought to have been the earliest animals with backbones. 
Question: Ancestors of hagfish are thought to have been the earliest?
[EX A]:
animals with backbone.