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: A bill is used for catching prey by some birds. 
Question: What is used by some birds to catch their prey?

Answer: a bill.


Question: Fact: fluid connective tissue carries oxygen. 
Question: What does fluid connective tissue carry?

Answer: oxygen.


Question: Fact: Biomass is the total mass of organisms in an environmental stage. 
Question: The total mass of organisms in an environmental stage is called what?

Answer:
biomass.