Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Every year your body replaces 98% of your atoms.
119
Your body is creating and killing about 2.4 million red blood cells per second.
17
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
The human body contains over a billion miles of DNA.
147
Your thumb is about the same size as your nose.
124