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: 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: Ejaculation of sperm can be inhibited by bacterial infection. 
Question: Bacterial infection can inhibit ejaculation of what?

Answer: sperm.


Question: Fact: Uneven heating of the Earth's surface can damage crops. 
Question: What is something uneven heating of the Earth's Surface can damage?

Answer:
Crops.