Yawns are more contagious among people with closer relationships.
163
Your body is creating and killing about 2.4 million red blood cells per second.
17
The human brain doesn't stop developing until about 25 years old.
102
One human hair can support 3 ounces.
191
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The human body contains over a billion miles of DNA.
147