Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The human body contains over a billion miles of DNA.
147
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
Yawns are more contagious among people with closer relationships.
163
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
One human hair can support 3 ounces.
191