People can apply for citizenship and receive a green card, get married to a U.S citizen, or have a parent who was born in the U.S
Politics.
Certain ethnicities have dominant religions, such as: Indian-Hindu, Chinese/Japanese-Buddhist, etc.
Race and language are also critical parts of ethnicity.
Giving each region a certain crop to focus on will force the nations to trade. For example, if corn is a huge cash crop for America, but not for the United Kingdom, they would likely trade with America. They would have low prices and high quantities to trade.
Answer:
After death of Aurangzeb, the Mughal empire became weaker and was done and dusted by 1764, after the battle of buxar. Though, Mughal emperors did try, but their rules extended till the boundary of red fort, untill it was extinguished formally by British in 1857.
