Your thumb is about the same size as your nose.
124
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Your body is creating and killing about 2.4 million red blood cells per second.
17
Yawns are more contagious among people with closer relationships.
163
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190