For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
Poor eyesight (myopia) is associated with higher IQ.
232
One human hair can support 3 ounces.
191