Why was the racial unrest in northern cities after wwi?

Why was control of the atlantic ocean essential to great britain’s success in world war 2

How did roman authorities treat conquered peoples? required them to pay taxes to rome replaced their local governments compelled them to adopt roman customs invited them to become roman citizens

How did the completion of the transcontinental railroad change the lives of american citizens? a-it increased the wealth of all americans and enabled them to travel more.b-it made cross-country travel too expensive for ordinary americans.c-it decreased the safety of americans who moved to settle the plains.d-it shortened travel time between the east and west for all americans.