ocr: ANIMAL EXCRETION NIMALS EXCRETE carbon dioxide to - the kidneys, where it is filtered A from respiration and nitrogen out to make a waste liquid called compounds from protein breakdown. urine. The urine goes to the bladder Birds and insects produce very for storage and then leaves the concentrated nitrogenous waste, body by the urethra. Some called uric acid. This is the white mammals also excrete water part oftheir droppings. and salts by sweating. In mammals, nitrogen waste in the form of urea is carried by the blood from the liver Urethra Mammal excretion This cat's kidneys are Kidney const ...