Yawns are more contagious among people with closer relationships.
163
In one day, adult lungs move about 10,000 litres of air.
11
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99