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.
--------
Question: Fact: Fertilization occurs when haploid gametes unite. 
Question: What occurs when haploid gametes unite?

Answer: fertilization.


Question: Fact: Passenger pigeons could not produce enough offspring. 
Question: What could not produce enough offspring?

Answer: passenger pigeons.


Question: Fact: Frogs have a three-chambered heart. 
Question: Frogs have a _-chambered heart.?

Answer:
three.