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: muscles contain cells. 
Question: What do muscles contain?
cells.

Fact: Most disinfectants contain solvents that can harm living things. 
Question: What product is likely to contain solvents that are harmful to living things?
disinfectants.

Fact: Earth 's magnetic patterns are used for finding locations by birds. 
Question: Earth 's magnetic patterns are used for finding locations by which creatures?

birds.