Enamel is hardest substance in the human body.
61
The average sperm cell swims at 8 inches per hour.
76
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Poor eyesight (myopia) is associated with higher IQ.
232
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73