Enamel is hardest substance in the human body.
61
Every year your body replaces 98% of your atoms.
119
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Yawns are more contagious among people with closer relationships.
163
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The average sperm cell swims at 8 inches per hour.
76
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The average person's skin weighs twice as much as their brain.
131