Enamel is hardest substance in the human body.
61
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
When you take a step, you are using up to 200 muscles.
886
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
One human hair can support 3 ounces.
191