Enamel is hardest substance in the human body.
61
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Poor eyesight (myopia) is associated with higher IQ.
232
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13