Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Enamel is hardest substance in the human body.
61
The average sperm cell swims at 8 inches per hour.
76
Your thumb is about the same size as your nose.
124
Every year your body replaces 98% of your atoms.
119
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118