Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human body contains over a billion miles of DNA.
147
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Chewing gum boosts your brain power.
285
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
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