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: ancestors of hagfish probably had backbones. 
Question: What did ancestors of hagfish probably have?
[EX A]: backbone.

[EX Q]: Fact: rain can break down rocks into smaller pieces. 
Question: What can rain do to rocks?
[EX A]: Break down.

[EX Q]: Fact: animals use ingestion to survive. 
Question: What do animals use ingestion for?
[EX A]:
survival.