Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Your body is creating and killing about 2.4 million red blood cells per second.
17
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
Poor eyesight (myopia) is associated with higher IQ.
232
The human brain doesn't stop developing until about 25 years old.
102
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
Enamel is hardest substance in the human body.
61