Enamel is hardest substance in the human body.
61
Yawns are more contagious among people with closer relationships.
163
Your body is creating and killing about 2.4 million red blood cells per second.
17
The human body contains over a billion miles of DNA.
147
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Your heart will pump about 212 million liters in its lifetime.
26
When you take a step, you are using up to 200 muscles.
886