Enamel is hardest substance in the human body.
61
Yawns are more contagious among people with closer relationships.
163
When you take a step, you are using up to 200 muscles.
886
Every year your body replaces 98% of your atoms.
119
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22