Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The human body contains over a billion miles of DNA.
147
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
The average sperm cell swims at 8 inches per hour.
76