An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
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It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your fingernails grow faster in summer.
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Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
21
Obsessive nose picking is called Rhinotillexomania.
101
Early American humans hunted car-size armadillos and used their shells for houses.
12
On average, there's 100 billion neurons in the human brain.
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