A sunflower is a plant and Amoeba is a protist. Structurally Amoeba is a unicellular, microscopic organism and its cell does not have cell wall, whereas sunflower plant is a multicellular organism and its cell have cell wall. Since Amoeba is made of only one cell, all the life processes such as nutrition, excretion and reproduction carried out by one cell. In sunflower plant is made of many cells. All the cells are arranged in tissues, organs and organ systems. specific organ system performs specific life process, for example digestion system performs the function of digestion. Thus, Amoeba is a simple organism and sunflower is a complex organism.