Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The average sperm cell swims at 8 inches per hour.
76
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Our Right Lungs takes more air than our left lung.
194