excretions
Excretion is the biological process of eliminating waste products of metabolism and other non-useful substances from an organism. It is distinct from secretion, which releases substances produced by cells for use elsewhere; excretion removes wastes from the body.
In animals, primary excretory organs include the kidneys, skin, lungs, and the digestive tract. The kidney’s
Nitrogenous waste varies by lineage: ammonia is soluble but highly toxic and is typically excreted by aquatic
Excretion also involves other routes, such as the liver’s processing of waste products that are then excreted
Excretion supports homeostasis by maintaining fluid and electrolyte balance, acid–base balance, and detoxification. Impairment of excretory