Yawns are more contagious among people with closer relationships.
163
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
The human brain doesn't stop developing until about 25 years old.
102
If your DNA was stretched out it would reach to the moon 6,000 times.
256
When you take a step, you are using up to 200 muscles.
886
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
The average sperm cell swims at 8 inches per hour.
76