Introduction - SS2 Biology Lesson Note

Excretion refers to the process by which waste products, toxins, and excess substances are removed from an organism's body. It is an essential biological process that helps maintain homeostasis and prevent the accumulation of harmful substances. Excretion eliminates metabolic waste products produced during cellular activities and regulates the balance of water, ions, and other substances within the body.

The excretory system is a collection of organs and structures responsible for excretion in organisms. It filters and eliminates waste products from the blood or body fluids and helps maintain the chemical balance and osmotic pressure of bodily fluids. The excretory system varies in complexity among different organisms.