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.
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Techopedia explains Permanent Virtual Circuit (PVC) A PVC is designed to eliminate the need to set up a call connection on frame relay, ATM or X.25 networks. Typically, the physical connections of a frame relay or supported network into various virtual circuits (VC) allow a physical connection to support multiple VCs simultaneously.