Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

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

A: The human body has as many as two trillion lymphocytes, and lymphocytes make up about 25% of all of what?
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Q: 2 hydrogen, 1 oxygen atoms combine to make up a molecule of water.

A: What atoms combine to make up a molecule of water?
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Q: A(n) operon consists of one or more genes that encode the proteins needed for a specific function.

A:
Which region of dna consists of one or more genes that encode the proteins needed for a specific function?
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