Enamel is hardest substance in the human body.
61
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
One human hair can support 3 ounces.
191
Chewing gum boosts your brain power.
285
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your heart will pump about 212 million liters in its lifetime.
26
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118