Excretion is the biological process through which organisms eliminate waste products generated from metabolic activities. This process is essential for maintaining homeostasis, as it helps regulate the internal environment by removing toxins and excess substances. In animals, excretion occurs through various organs, such as the kidneys, liver, and skin, while in plants, it can involve the shedding of leaves or the release of substances through stomata. Overall, excretion is crucial for the health and survival of living organisms.