Yawns are more contagious among people with closer relationships.
163
The human body contains over a billion miles of DNA.
147
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Your thumb is about the same size as your nose.
124
The average sperm cell swims at 8 inches per hour.
76
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22