The correct answer is Urea.
Nitrogenous wastes are metabolic wastes products that contain nitrogen. Urea and uric acid are the most common nitrogenous waste products in terrestrial animals; freshwater fish excrete ammonia and marine fish excrete both urea and trimethylamine oxide. The excretory system serves to remove these nitrogenous waste products, as well as excess salts and water, from the body.
