Urea is an excretory product which is generally produced by the breakdown of proteins in humans. The excretory products that are produced by the plants such as gums, oils, latex, resins, etc. are stored in plant parts like barks, stems, leaves, etc. The plants get rid of these wastes by shedding of leaves, peeling of bark and felling of fruits. Whereas, excess water is lost through the process of transpiration.