The colon is the last portion of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided (largely bacteria) fermentation of unabsorbed material occurs. In mammals, the colon consists of four sections: the ascending colon, the transverse colon, the descending colon, and the sigmoid colon. The colon, cecum, and rectum make up the large intestine.