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: Pollution is usually harmful to population size of a species. 
Question: What is usually harmful to the population size of a species?

Output: Pollution.


Input: Consider Input: Fact: cows can communicate with sounds, chemicals or visual cues. 
Question: what can communicate with sounds, chemicals or visual cues?

Output: cows.


Input: Consider Input: Fact: animals attract with smells. 
Question: What do animals use to reproduce?


Output: smells.