Yawns are more contagious among people with closer relationships.
163
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
One human hair can support 3 ounces.
191
Your body is creating and killing about 2.4 million red blood cells per second.
17
Every year your body replaces 98% of your atoms.
119
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18