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.

[Q]: Fact: Earthworm burrows help aerate soil, which is essential for growing plants. 
Question: Earthworm burrows help aerate soil, which is essential for what?
[A]: growing plants.


[Q]: Fact: warblers are nocturnal and travel long distances at night. 
Question: What are nocturnal and travel long distances at night?
[A]: warblers.


[Q]: Fact: water causes light rays to bend. 
Question: What happens to light rays in water?
[A]:
they bend.