Enamel is hardest substance in the human body.
61
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217