Yawns are more contagious among people with closer relationships.
163
Your thumb is about the same size as your nose.
124
When you take a step, you are using up to 200 muscles.
886
Your body is creating and killing about 2.4 million red blood cells per second.
17
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
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
Every year your body replaces 98% of your atoms.
119
The human body contains over a billion miles of DNA.
147