For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Your body is creating and killing about 2.4 million red blood cells per second.
17
The average person's skin weighs twice as much as their brain.
131
The human brain doesn't stop developing until about 25 years old.
102
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55