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: Sponges trap and digest food with specialized cells. 
Question: What do sponges use to collect and digest food?
[A]: specialized cells.


[Q]: Fact: Vertebrates have a complete digestive system and a closed circulatory system. 
Question: vertebrates have a complete digestive system and a what?
[A]: closed circulatory system.


[Q]: Fact: aging is associated with short telomeres. 
Question: What is associated with aging?
[A]:
Short telomeres.