For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
If your DNA was stretched out it would reach to the moon 6,000 times.
256
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Enamel is hardest substance in the human body.
61
The average sperm cell swims at 8 inches per hour.
76
The average person's skin weighs twice as much as their brain.
131
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127