If you hold farts in during the day, they'll just come out when you sleep.
16
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
There's 100 trillion good bacteria living in your body.
17
The human body contains over a billion miles of DNA.
147
In one day, adult lungs move about 10,000 litres of air.
11
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
