Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Poor eyesight (myopia) is associated with higher IQ.
232
The average sperm cell swims at 8 inches per hour.
76
Yawns are more contagious among people with closer relationships.
163
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
The human body contains over a billion miles of DNA.
147
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197