Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: Renewable energy sources emit fewer or no greenhouse gases.

Answer: What type energy sources emit fewer or no greenhouse gases?


Question: The human body has as many as two trillion lymphocytes, and lymphocytes make up about 25% of all of leukocytes.

Answer: The human body has as many as two trillion lymphocytes, and lymphocytes make up about 25% of all of what?


Question: Gravity force increases a slide downhill and decreases a slide uphill.

Answer:
What force increases a slide downhill and decreases a slide uphill?