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The average office desk has 400 times more bacteria on it than a toilet.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
Vaccines prevent between 2.5 and 4 million deaths every year.
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."
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