Enamel is hardest substance in the human body.
61
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Every year your body replaces 98% of your atoms.
119
One human hair can support 3 ounces.
191
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
If you are cold you are more likely to be hungry because you use energy to keep warm.
143