"Your body is an incredible machine that can run for more than 80 years without batteries, can self-propel over land and water, can heal itself from most common ailments, and can pair with another of its kind to reproduce. This updated, fully illustrated, easy-to-understand guide from National Geographic explores the intricate systems that make up the marvelous human body--from head to toe, inside and out. Beautifully designed and brimming with fascinating...