In the concentric zone model of urban growth, cities tend to grow outward from a central area in a series of growth rings.
grow inward from the suburbs in a series of growth rings,
develop in a series of corridors that extend from the downtown.
include more than one center around which activities revolve.
be surrounded by a beltway that connects suburbs to inner cities,

workers of lowell mills were greatly benefited for the waltham type of work which was more a paternalist kind, trying to protect the integrity of this little girls coming from small farmers and providing an adequate place of work, this in an effort to avoid the issues of bad place conditions and immorality that the people in bigger industrialized cities of great britain were experimenting.

the answer should be a. the sui empire, the tang empire extended from korea in the west to manchuria in the east.