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: expansion can cause fatigue. 
Question: what can cause fatigue?
expansion.

Fact: Hawks have an increased population size. 
Question: What has an increased population size?
Hawks.

Fact: actinomycetes may spread directly from one person to another. 
Question: what may spread directly from one person to another?

actinomycetes.