Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Enamel is hardest substance in the human body.
61
The human body contains over a billion miles of DNA.
147
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Most of us have microscopic, worm like mites named Demodex that live in our eyelashes and have claws and a mouth.
-137