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The average adult has about 21 square feet of skin.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Your heart beats over 36 million times a year.
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
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