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 uses approximately as much energy as a 10 watt light bulb.
120
Every year your body replaces 98% of your atoms.
119
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Poor eyesight (myopia) is associated with higher IQ.
232
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