The is a process wherein people have been compelled to move from rural areas and have been attracted to cities due to a variety of economic changes.

I believe the answer is: Urbanization

Urbanization started to occur ever since the industrial revolution period. Before the industrial revolution, most jobs were located on rural area since most of the jobs were related to farming. After industrial revolution, manufactures provide the largest job opportunities, which make it shifted to urban area.

the united states has a federal government. the president is the head of the federal government of the united states. however, each state forms its government for administration purposes. the powers of the state governments are exercised within restricted state boundaries. and citizens participate in this government by voting.