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: animals use sound to find a mate. 
Question: What do animals use to find a mate?
sound.

Fact: Genetic traits are passed down to offspring through chromosomes. 
Question: How are genetic traits passed down to offspring?
Through chromosomes.

Fact: Plants detect light and dark because of their circadian rhythm. 
Question: What do plants detect because of their circadian rhythm?

Light and dark.