Your body is creating and killing about 2.4 million red blood cells per second.
17
Enamel is hardest substance in the human body.
61
The human brain doesn't stop developing until about 25 years old.
102
When you take a step, you are using up to 200 muscles.
886
Yawns are more contagious among people with closer relationships.
163
It takes about 20 seconds for a red blood cell to circle the whole body.
102