The adult human brain weighs about 3 pounds (1,300-1,400 g).
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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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Enamel is hardest substance in the human body.
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The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
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The largest cell in the human body is the female egg and the smallest is the male sperm.
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Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
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When you take a step, you are using up to 200 muscles.
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