Your stomach produces a new layer of mucus every two weeks so that it doesn't digest itself.
160
Although African-Americans make up only 13% of the U.S. population, they accounted for one half of the estimated new HIV/AIDS diagnoses in 2004.
70
Your ribs move about 5 million times a year, every time you breathe!
60
Every hour one billion cells in the body must be replaced.
17
It takes about 20 seconds for a red blood cell to circle the whole body.
102
A person can live without food for about a month, but only about a week without water.
156
Your heart rate can rise as much as 30% during a yawn.
69
Fingernails grow nearly 4 times faster than toenails.
31