It was primarily the development of agriculture that led to the development of the first city states, since this allowed for there to be a surplus of food, which allowed people to have labor specialization.
That is because the vast majority of Native Americans died in the period. This was mostly due to diseases that the Europeans brought with them and against which they didn't have the immunity. Many also died in wars and in reservations, but mostly due to diseases. The Europeans flourished and developed successful colonies, which led to the modern times.
The correct rule is "a person could not marry a person of lower social standing."
If you are born into a lower social class & became wealthier, had good behavior, owned more land, etc., it wouldn't change your position.
You are going to be stuck with the same social class your entire life, same thing would happen if your parents were in the lower social class & you became more successful, you would still be in the same class as your parents. You would work the jobs they worked & go through what they have to go through. Though I believe later on it was socially acceptable to marry to a lower class, but it was taboo.
Hopefully this helped of some sort!
Answer: Scribes, Merchants, Slaves
Explanation: 90% sure.
