If you're referring to the independence of the USA from England,
the country celebrates that occasion on July 4 of each year.
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b. they were ruled by emperors
The Aztec and Inca had a common structure in that they were both ruled by emperors.
Answer:
Knowing others is intelligence; knowing yourself is true wisdom. mastering others is strength; mastering yourself is true power. if you realize that you have enough, you are truly rich, "And the cause of not following your heart, is in spending the rest of your life wishing you had."
Town lifestyle (I assume you mean by this: a settled lifestyle , so that it contrasts with the nomadic lifestyle) comes with more security: you can store your food reserves and plan for the future.
nomadic lifestyle gives you more flexibility but less security: you can travel elsewhere if your fodosource is runnign low... but usually this is not as good of a food source as a settled lifestyle. One other possible advantage could be being merchants: nomads can benefit from a trade.