Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Every year your body replaces 98% of your atoms.
119
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your body is creating and killing about 2.4 million red blood cells per second.
17
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
Your thumb is about the same size as your nose.
124