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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.
There are 20 feet of blood vessels in each square inch of human skin.
Human kidneys will clean about 1 million gallons of blood in an average lifetime.
Vaccines prevent between 2.5 and 4 million deaths every year.
Medication errors are more common among seriously ill patients than with those with minor conditions.
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