instruction:
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: animals use glucose for energy. 
Question: what do animals use for energy?
answer:
glucose.


question:
Fact: all cells have cellular material inside the plasma membrane. 
Question: what has cellular material inside the plasma membrane?
answer:
all cells.


question:
Fact: Mutualism adds to the complexity of species interactions. 
Question: What is something that adds complexity to species interactions?
answer:

mutualism.