Why was the Pacific Railroad Act necessary?

How does désir represent the diversity of europe today? how did the 1400s and 1500s affect the religious diversity of europe? how might cultural diversity in a place like germany affect everyday life? what are two reasons some europeans might find immigration to be an advantage? what are two reasons some might find it to be a disadvantage? why do you think languages and culture spread more easily in europe now than in the past?

What was the name of the theory that said that if one country in a region fell to communism, others would surely follow? 1) domino theory 2) arms race 3) brinkmanship 4) containment theory

Do you think the united states experiences amalgamation, assimilation, or pluralism? why?