Our body produces various wastes during the process of digestion and other metabolic reactions. It is necessary to remove these wastes because they are toxic for our body.In the Urinary system, Kidneys eliminate excess water, toxins and urea.This helps in maintaining electrolytic balance.The sweat excreted from the skin contain water, minerals, lactate and urea. This helps in maintaining body temperature and homeostasis.
Because these wastes are toxic for our body. If they are not removed then they will increase in concentration and may interfere in chemical reactions.