Sugar (commonly sucrose, C₁₂H₂₂O₁₁) is made up of Carbon, Hydrogen, and Oxygen atoms chemically combined in a fixed ratio. Therefore, sugar is a compound. Air is a mixture of gases like nitrogen, oxygen, argon, carbon dioxide, etc. Milk is a complex mixture of water, fats, proteins, carbohydrates, minerals, etc. Tea is an aqueous mixture containing compounds extracted from tea leaves.