Answer:
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. Today the system of classification includes six kingdoms.
Explanation:
Ocean currents are caused by many things. One of the main cause is the wind direction. Another cause would be density differences that is made of the temperature and the salinity of water and also currents can also be caused by events like earthquakes causing tsunamis.