Yawns are more contagious among people with closer relationships.
163
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Your thumb is about the same size as your nose.
124
Every year your body replaces 98% of your atoms.
119
The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18