The human brain doesn't stop developing until about 25 years old.
102
Your body is creating and killing about 2.4 million red blood cells per second.
17
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Yawns are more contagious among people with closer relationships.
163
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
The average sperm cell swims at 8 inches per hour.
76