Which substances does our body excrete through the skin liver alimentary canal?

The body excretes various substances through the skin, liver, and alimentary canal. Through the skin, it primarily eliminates sweat, which contains water, salts, and small amounts of urea. The liver processes toxins and metabolic waste, excreting bile, which contains bilirubin and cholesterol. The alimentary canal removes undigested food and waste products, including fiber and other non-absorbable substances.