Every year your body replaces 98% of your atoms.
119
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
It takes about 20 seconds for a red blood cell to circle the whole body.
102
One human hair can support 3 ounces.
191
Your heart will pump about 212 million liters in its lifetime.
26
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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