Between 1820 and 1880, millions of immigrants moved together in groups and settled alongside one another in certain areas called what regions?

Which of these is not a criticism of the concentric zone model? it does not accurately describe cities after the rise of suburban development. it only applies to cities that grew after the development of the automobile. it assumes that inner-city areas will always be repurposed instead of abandoned. it places too much importance on the traditional central business district.