What triggered typhoid and cholera epidemics in American cities in the late 1800's?

explanation:

i think it is in quadrant 4.

the five year plans were part of a command economy. there was little choice in what would be emphasized for the current 5 year period.

the answer to democracy or totalitarianism is a bit harder. in stalin's time, russia was totalitarian. now that's not entirely true. putin has moved towards at least the boundary.

the colonial period, since this was a time of mass immigration from a variety of people from europe.

b. a system of government that provided a model for the united states.