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Multiple sclerosis is a condition wherein the body's nervous system is weakened by an autoimmune reaction that attacks the myelin sheaths of neurons.
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."
Vaccines prevent between 2.5 and 4 million deaths every year.
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
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