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: Starfish lack respiratory and excretory systems. 
Question: What is an example of an animal that lacks a respiratory and excretory system?

Output: Starfish.


Input: Consider Input: Fact: roundworms may be free-living or live off a host. 
Question: aside from free-living, where else can roundworms exist?

Output: live off a host.


Input: Consider Input: Fact: Having no natural predators reduces the probability of extinction. 
Question: What event does the lack of natural predators prevent?


Output: extinction.