For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Chewing gum boosts your brain power.
285
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The average sperm cell swims at 8 inches per hour.
76
Yawns are more contagious among people with closer relationships.
163
It takes about 20 seconds for a red blood cell to circle the whole body.
102
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
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22