Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
Your thumb is about the same size as your nose.
124
Your heart will pump about 212 million liters in its lifetime.
26
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Most of us have microscopic, worm like mites named Demodex that live in our eyelashes and have claws and a mouth.
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