Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
One human hair can support 3 ounces.
191
Enamel is hardest substance in the human body.
61
Yawns are more contagious among people with closer relationships.
163
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Your body is creating and killing about 2.4 million red blood cells per second.
17
It takes about 20 seconds for a red blood cell to circle the whole body.
102