Answer:
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. The Six Kingdoms: Plants, Animals, Protists, Fungi, Archaebacteria, Eubacteria.
Step-by-step explanation: