It takes about 20 seconds for a red blood cell to circle the whole body.
102
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
When you take a step, you are using up to 200 muscles.
886
Your thumb is about the same size as your nose.
124
The average person's skin weighs twice as much as their brain.
131
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