The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Your body is creating and killing about 2.4 million red blood cells per second.
17
The human brain doesn't stop developing until about 25 years old.
102
When you take a step, you are using up to 200 muscles.
886
The human body contains over a billion miles of DNA.
147
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515