Enamel is hardest substance in the human body.
61
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The human body contains over a billion miles of DNA.
147
Yawns are more contagious among people with closer relationships.
163
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
Poor eyesight (myopia) is associated with higher IQ.
232
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
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46