Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your body is creating and killing about 2.4 million red blood cells per second.
17
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Chewing gum boosts your brain power.
285
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Enamel is hardest substance in the human body.
61
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Poor eyesight (myopia) is associated with higher IQ.
232