The Six Kingdoms. When Linnaeus developed his system of classification, there were only two kingdoms, Plants and Animals. But the use of the microscope led to the discovery of new organisms and the identification of differences in cells.A two-kingdom system was no longer useful.Today the system of classification includes six kingdoms.he Six Kingdoms. When Linnaeus developed his system of classification, there were only two kingdoms, Plants and Animals. But the use of the microscope led to the discovery of new organisms and the identification of differences in cells.
About PTC PTC (NASDAQ: PTC) is a global software company that delivers a technology platform and solutions to help companies design, manufacture, operate, and service things for a smart, connected world.
PTC CAD is a suite of 2D and 3D product design software used to create, analyze and view product designs. PTC Creo software was released in June 2011 to replace and supersede PTCâs products formerly known as Pro/ENGINEER, CoCreate, and ProductView.