Concept:Different plant tissues have specific functions; the supporting tissues give strength and hold the plant upright.Explanation:Collenchyma provides flexible support to young stems and leaves.Xylem gives mechanical strength as wood or water-conducting tissue.Parenchyma can also offer some support when its cells are turgid.Phloem is mainly for transporting sugars and food substances.Phloem does not provide mechanical support to flowering plants.Answer:D. Phloem