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: blood traveling to the heart is deoxygenated. 
Question: Blood traveling to the heart is?

Answer: deoxygenated.


Question: Fact: The mass of the Earth helps cause flowing rivers. 
Question: Which aspect of the Earth is needed to have flowing rivers?

Answer: Mass.


Question: Fact: balanced forces exert mutually on an object making it remain stationary. 
Question: What is likely to exert mutually on an object, making the object remain stationary?

Answer:
balanced forces.