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: Eggs are fertilized during reproduction. 
Question: What happens during reproduction?
eggs are fertilized.

Fact: water flow through soil is variable. 
Question: What is the rate of water flow of soil?
variable.

Fact: lemon changes the color of litmus paper from blue to red. 
Question: What changes the color of litmus paper from blue to red?

lemon.