Given a scientific question, generate a correct answer to it.

Q: A black solid by itself, this element is incredibly important because of what it makes when it combines with many other elements, including oxygen?

A: carbon
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Q: The urea cycle, a set of biochemical reactions that produces urea from ammonium ions to prevent toxicity, occurs to some extent in the kidney, but primarily in what organ?

A: liver
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Q: What two measurements are multiplied to find the area of a rectangle?

A:
length and width
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