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Human kidneys will clean about 1 million gallons of blood in an average lifetime.
Blood is approximately twice as thick as water because of the cells and other components found in it.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
If you could remove all of your skin, it would weigh up to 5 pounds.
About 100 new prescription or over-the-counter drugs come into the U.S. market every year.
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