In the late 1800's most "new" immigrants to the United States came from

I'm pretty sure that "new" immigrants from southern and eastern europe came from southern and eastern Europe

hello!

according to the passage the most suitable options are two. the first one is "by leading the aef to victory in several key battles" like the battle of saint- mihiel and the battle of cantigny mentioned in the passage you copied here. the second one is "by the aef and allied forces defeat germany" since the passage says that his army destroy the german resistance in the meuse- argonne offensive. and also, "by insisting that the aef operate as an independent force".

hope this