What are the differences between autotrophic nutrition and heterotrophic nutrition? Here plants utilize the energy of sunlight. It uses this energy plant to convert carbon dioxide and water into complex carbohydrates. They are producers. Cells of plant use this Complex material produced here to produce energy. Plants and blue-green algae are examples of autotrophs. Here complex food obtained from the plant is utilized to produce the energy. There is no formation of complex carbohydrates. And no energy of sunlight used. All animals and fungi are heterotrophs. They are consumers.