Enamel is hardest substance in the human body.
61
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The average sperm cell swims at 8 inches per hour.
76
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55