The collapse of the roman empire most likely empower the catholic church because

Many Europeans were trying to find the way that kept them united

Explanation:

Catholic religion became the ideology that kept the society of that time as one, with the fall of the Roman empire many people migrated from the urban areas to the rural ones, due to this education suffered a major change, and it started to decline. Catholic church took many functions that the government used to have  and this obviously also helped to its expansion.

i dont know. sorry : (

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