The correct answer to this open question is the following.
Social classes began to be more notorious in the US society when industrialization in the North region became the dominant driver of the economic force. Wealth started to be distributed unequally among members of society that started to live by different standards. It also included their view about social issues such as slavery. Wealthy families associated with other rich families to protect their economic interests. Meanwhile, the middle class, formed by merchants and artisans, worked daily to maintain a decent level of living. So they based their results in hard work, preparation, and persistence. They couldn't afford a day off because they feared that they could lose their small business and fall to the low-class level, where workers earned low wages and suffered to make a living. If we are honest, not much has changed since those days, compared to what we era living now in modern classy society, where just a small number of wealthy families possess 80% of the wealthiness, while the majority of the people try to make a living with the rest 20%.
The creation of distinctive classes in the North drove striking new cultural developments. Even among the wealthy elites, northern business families, who had mainly inherited their money, distanced themselves from the newly wealthy manufacturing leaders. Regardless of how they had earned their money, however, the elite lived and socialized apart from members of the growing middle class. The middle class valued work, consumption, and education and dedicated their energies to maintaining or advancing their social status. Wage workers formed their own society in industrial cities and mill villages, though lack of money and long working hours effectively prevented the working class from consuming the fruits of their labor, educating their children, or advancing up the economic ladder.
The 17th amendment was ratified in 1913. So before the ratification, the senators were chosen by the states legislature, but after the ratification it was a popular vote that disided the senator.
