oxygen is a mean of vibrations & calcium is a kind of element & oxygen is a kind of element ->  calcium, carbon, and oxygen are three elements  calcium, carbon, and space are third come & calcium carbonate is made of calcium, carbon, and oxygen -> calcium carbonate is made of three elements calcium carbonate is made of three elements  calcium carbonate is made of three elements & a simple is made of one or more data chemically combined -> calcium carbonate is a kind of compound