kidney
Kidneys
skin
Platypuses have a cloaca, which is used for both excretion and reproduction.
The major organ systems involved in metabolism are the digestive system, which breaks down food into nutrients for energy, and the endocrine system, which regulates metabolism through hormones. The major organ systems involved in excretion are the urinary system, which removes waste from the blood in the form of urine, and the respiratory system, which eliminates carbon dioxide.
The skin is considered an organ of excretion because it sweats, getting rid of toxins and certain mineral salts.
Worms use their skins for excretion mostly.
Kidneys
The Anus
The primary organ of excretion is the kidney. Kidneys filter waste products from the blood to produce urine, which is then excreted from the body.
The kidney is the main organ, that is responsible for the excretion of waste products. Other organs of excretion are your liver, lungs and skin.
lung