The average person's skin weighs twice as much as their brain.
131
Enamel is hardest substance in the human body.
61
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Every year your body replaces 98% of your atoms.
119
The average sperm cell swims at 8 inches per hour.
76
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