Yawns are more contagious among people with closer relationships.
163
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
Every year your body replaces 98% of your atoms.
119
Your thumb is about the same size as your nose.
124
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The average sperm cell swims at 8 inches per hour.
76
The human brain doesn't stop developing until about 25 years old.
102