What is the name of the theory that explains why mountain ranges in africa and south america line up?

Tanya was used to using word, and she did some work for her brother mike, who was using wordperfect. tanya was quickly able to use wordperfect for windows with little difficulty, since many of the commands for it were the same as the commands for word. tanya's ability to use wordperfect best illustrates:

Immigrants arriving in the united states during the late 1800s experienced many difficulties. which of the following was a problem which large numbers of immigrants faced?

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