Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Every year your body replaces 98% of your atoms.
119
When you take a step, you are using up to 200 muscles.
886
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Yawns are more contagious among people with closer relationships.
163
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Poor eyesight (myopia) is associated with higher IQ.
232
Enamel is hardest substance in the human body.
61