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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
One human hair can support 3 ounces.
191
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149