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.

Input: Consider Input: Fact: Most animals without backbones have a nervous system. 
Question: Which type of system do most animals without backbones have?

Output: Nervous system.


Input: Consider Input: Fact: crocodiles have good eyesight and a keen sense of smell. 
Question: What has good eyesight and a keen sense of smell?

Output: crocodiles.


Input: Consider Input: Fact: Pelycosaurs are extinct animals that formed another animal classification called Therapsids. 
Question: What is the animal classification that the Pelycosaurs formed?


Output: Therapsids.