The average person's skin weighs twice as much as their brain.
131
Enamel is hardest substance in the human body.
61
One human hair can support 3 ounces.
191
The average sperm cell swims at 8 inches per hour.
76
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain doesn't stop developing until about 25 years old.
102
The human body contains over a billion miles of DNA.
147
Your heart will pump about 212 million liters in its lifetime.
26