Enamel is hardest substance in the human body.
61
The average sperm cell swims at 8 inches per hour.
76
The average person's skin weighs twice as much as their brain.
131
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
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
Your heart will pump about 212 million liters in its lifetime.
26
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
The human brain doesn't stop developing until about 25 years old.
102