excess, unnecessary materials from the body fluids of an organism,
so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excretory systems is the elimination of the waste products of metabolism and to drain the body of used up and broken down components in a liquid and gaseous state. In humans and other amniotes (mammals, birds and reptiles) most of these substances leave the body as urine and to some degree exhalation, mammals also expel them through sweating.It includes
Urinary system
Respiratory system
Integumentary system
Billary system
Gastrointestinal tract