<P> Medicines obtained from stems include quinine from the bark of cinchona trees, camphor distilled from wood of a tree in the same genus that provides cinnamon, and the muscle relaxant curare from the bark of tropical vines . </P> <P> Wood is used in thousands of ways, e.g. buildings, furniture, boats, airplanes, wagons, car parts, musical instruments, sports equipment, railroad ties, utility poles, fence posts, pilings, toothpicks, matches, plywood, coffins, shingles, barrel staves, toys, tool handles, picture frames, veneer, charcoal and firewood . Wood pulp is widely used to make paper, paperboard, cellulose sponges, cellophane and some important plastics and textiles, such as cellulose acetate and rayon . Bamboo stems also have hundreds of uses, including paper, buildings, furniture, boats, musical instruments, fishing poles, water pipes, plant stakes, and scaffolding . Trunks of palm trees and tree ferns are often used for building . Stems of Reed are an important building material for use in thatching in some areas . </P> <P> Tannins used for tanning leather are obtained from the wood of certain trees, such as quebracho . Cork is obtained from the bark of the cork oak . Rubber is obtained from the trunks of Hevea brasiliensis . Rattan, used for furniture and baskets, is made from the stems of tropical vining palms . Bast fibers for textiles and rope are obtained from stems include flax, hemp, jute and ramie . The earliest paper was obtained from the stems of papyrus by the ancient Egyptians . </P> <P> Amber is fossilized sap from tree trunks; it is used for jewelry and may contain ancient animals . Resins from conifer wood are used to produce turpentine and rosin . Tree bark is often used as a mulch and in growing media for container plants . It also can become the natural habitat of lichens . </P>

Which of the following refers to the function of plants