There are about 1,400 different species of bacteria in your belly button.
10
The average person's skin weighs twice as much as their brain.
131
In one day, adult lungs move about 10,000 litres of air.
11
If you hold farts in during the day, they'll just come out when you sleep.
16
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Your body is creating and killing about 2.4 million red blood cells per second.
17
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
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197