For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
The human brain doesn't stop developing until about 25 years old.
102
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your body is creating and killing about 2.4 million red blood cells per second.
17
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The largest cell in the human body is the female egg and the smallest is the male sperm.
682