what was the reason for the groth of cities?

Answer 1

Well, it depends on the area and the time, but in general:
* The ready supply of jobs
* Better infrastructure (roads, schools, hospitals)
* Not as isolated as the rural areas (although some would see this as a negative)
* Better chance for advancement

Answer 2

first farming was the way to live, and as our nation became industrialized, with industries to work for, people moved to cities to get better jobs.

Answer 3

during what period? there was many different reasons during diferent times