Here's a breakdown:

* Excretion is the process of removing metabolic waste products from the body.

* Metabolic waste products are substances that are produced as a result of the body's normal metabolic processes. These can include:

* Urea: A nitrogenous waste product from protein breakdown.

* Carbon dioxide: A waste product from respiration.

* Water: A product of various metabolic processes.

* Excess salts: From the diet and metabolic processes.

The organs responsible for excretion include:

* Kidneys: Filter blood and produce urine, removing urea, excess water, and salts.

* Lungs: Exhale carbon dioxide, a waste product of respiration.

* Skin: Sweats, removing excess water, salts, and a small amount of urea.

* Liver: Processes and filters waste products from the blood.