/kloc-what are the reasons why Asia, Europe and Africa immigrated to the United States in the 0/9th century?

Europeans have opened up new routes. A large number of Europeans went to America to look for gold knowledge, opened up manors and slaughtered Indian Taoist priests, resulting in a shortage of labor. Africa is the offspring of people who were sold into slavery in the past. Later, the slave trade was banned, and Asians found it easy to make money everywhere in the United States before they found themselves working in the United States.