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.

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

Fact: animal fur can help plants grow. 
Question: What can help plants grow?
Animal fur.

Fact: The Woolly Mammoth lived when the planet was buried in snow and ice. 
Question: When did the woolly mammoth live?

when planet was buried in snow.