Yawns are more contagious among people with closer relationships.
163
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
Every year your body replaces 98% of your atoms.
119
The human body contains over a billion miles of DNA.
147