The adult human brain weighs about 3 pounds (1,300-1,400 g).
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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
The human brain doesn't stop developing until about 25 years old.
102
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
When you take a step, you are using up to 200 muscles.
886
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
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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