Enamel is hardest substance in the human body.
61
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Yawns are more contagious among people with closer relationships.
163
Every year your body replaces 98% of your atoms.
119
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
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
Your heart will pump about 212 million liters in its lifetime.
26
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217