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Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
The average adult has about 21 square feet of skin.
Between 1999 and 2012, American adults with high total cholesterol decreased from 18.3% to 12.9%
Your heart beats over 36 million times a year.
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