For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Yawns are more contagious among people with closer relationships.
163
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
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
The largest cell in the human body is the female egg and the smallest is the male sperm.
682