For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Every year your body replaces 98% of your atoms.
119
The human brain doesn't stop developing until about 25 years old.
102
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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Poor eyesight (myopia) is associated with higher IQ.
232