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: Breathing provides one substance transported by the blood. 
Question: What process provides one substance transported by the blood?

Answer: breathing.


Question: Fact: penguins are endothermic tetrapod vertebrates. 
Question: what are endothermic tetrapod vertebrates?

Answer: penguins.


Question: Fact: birds use muscles for flight. 
Question: What do birds use for flight?

Answer:
muscles.