Your body is creating and killing about 2.4 million red blood cells per second.
17
Enamel is hardest substance in the human body.
61
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!
197
Poor eyesight (myopia) is associated with higher IQ.
232
Chewing gum boosts your brain power.
285
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515