A batch of countries or colonies ruled by emperors, duke or a duchess.
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As changes to the Earths climate occur, organisms within will be given the natural selection all animals are. Those being, die off and not adapt, or adapt “evolve” to the new climate and survive. An example is the bear, polar bears adapted to winter climates by having a white fur coat to blend in, while grizzlies have a brown coat to blend in with shrubbery or the soil.
In the traditional Hindu caste system the status of a person was usually determined by birth.