The average sperm cell swims at 8 inches per hour.
76
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
The human body contains over a billion miles of DNA.
147
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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