Concept:Xylem is the plant vascular tissue that transports water and minerals and also provides physical support.Explanation:The xylem carries water and dissolved minerals from the roots to other parts of the plant.Its thick-walled cells add strength and help support the stem.Manufacturing food is the function of leaves, reducing water loss involves stomata, and conducting manufactured food is the role of phloem.Thus, among the options, strengthening the stem is a correct function of the xylem.Answer:A. strengthening the stem