[Solved] Assume that Verizon Wireless is interested in studying the pricing expectations of its customers. If the study calls for selecting at random 100 people from each of three age groupings, ____ sampling is being used. A) random B) stratified C) quota D) area E) experimental Gymnosperms: A group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes, characterized by their naked seeds not enclosed in an ovary. Angiosperms: A large group of plants characterized by having flowers and producing seeds enclosed within a fruit. Xylem: Complex vascular tissue of plants; cell walls of its dead tracheids and vessel elements form tubes that distribute water and mineral ions through the plant body. Tracheids: Component of xylem. Tapered cells that die when mature; pitted walls that remain interconnect with other tracheids to form water-conducting tubes.