This process is broken down into seven layers; Application Layer, Presentation Layer, Session Layer, Transport Layer, Network Layer, Data Link Layer, and Physical Layer. When a person communicates to another person on a network the information passes through these layers.
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. The word for earth in Greek is geo, so we call this idea a geocentric theory.
Claudius Ptolemy, an Egyptian geographer, mathematician, and astronomer, is credited with the Ptolemaic Model of the solar system. His model posited not only that the Earth was the center of the entire universe and assumed that the planets all moved in epicycles--small circles--that also moved alongâ¦.