Poor eyesight (myopia) is associated with higher IQ.
232
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your thumb is about the same size as your nose.
124
Enamel is hardest substance in the human body.
61
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515