Through digestion; undigestible materials are removed from the body via the rectum and anal canal.
The integumentary, respiratory, digestive, urinary. Systems by association include the circulatory and lymphatic (and to a degree the muscular).
The organs remove waste from the body so that you can stay healthy and clean in order to achieve certain tasks like preventing infections and acne.
Nothing alive can live in a pool of it's own waste products ... that includes the cells of your body.
through the kidneys and liver through the kidneys and liver