For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The average sperm cell swims at 8 inches per hour.
76
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Every year your body replaces 98% of your atoms.
119
Your body is creating and killing about 2.4 million red blood cells per second.
17
Yawns are more contagious among people with closer relationships.
163
When you take a step, you are using up to 200 muscles.
885