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Vaccines prevent between 2.5 and 4 million deaths every year.
There are 20 feet of blood vessels in each square inch of human skin.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
The human body produces and destroys 15 million blood cells every second.
In the United States, an estimated 50 million unnecessary antibiotics are prescribed for viral respiratory infections.
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