When you take a step, you are using up to 200 muscles.
886
Yawns are more contagious among people with closer relationships.
163
The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
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
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Your thumb is about the same size as your nose.
124