Fat cells develop steadily from birth to the early twenties. Research shows that it's only the size of the cells in individuals that differs. Learn more about fat and metabolism in "Extreme Bodies" on Discovery Channel.
WHAT'S INSIDE: HUMAN BODY
- Body Parts
- Body Systems
Healthy digestion involves the whole body. Learn about the processes and body parts that go into digestion.
Think it's a hassle when your car breaks down? Try finding a spare organ when your body gives out. Thanks to years of research, scientists are now amassing a "body shop"Ã‚Â of sorts, dealing not in tires or mufflers, but in bladders, bones and breasts.