Enamel is hardest substance in the human body.
61
Your thumb is about the same size as your nose.
124
The average sperm cell swims at 8 inches per hour.
76
One human hair can support 3 ounces.
191
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
It takes about 20 seconds for a red blood cell to circle the whole body.
102