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
When you take a step, you are using up to 200 muscles.
886
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197