Asap 5 questions i need them now brainliiest and 48 points 1) which of the following represents the belief used to justify westward expansion of america's borders in the 1800s? monroe doctrine manifest destiny adams-onis treaty missouri compromise 2) what was the main idea of the monroe doctrine? it was a proclamation of war between the u. s. and mexico. it was a warning for european countries to stop colonization in the western hemisphere. it was an agreement to give territories to the native americans. it was a list of complaints from the u. s. to european countries. 3) what was a main outcome of the adams-onis treaty? texas became a u. s. territory florida became a u. s. territory texas became a spanish territory florida became a spanish territory 4) how were the monroe doctrine and the adams-onis treaty similar? both were treaties which protected native american lands. both were reasons for the war between the u. s. and mexico. both were actions to expand borders and u. s. influence. both were agreements signed between the u. s. and spain. 5) how did this map change following the treaty of washington in 1846? the oregon country was divided between britain and the united states at the 49th parallel. the oregon country was split into the washington and oregon territories using the 49th parallel as the new boundary. the boundary between the oregon country and mexico was shifted from the 42nd parallel to the oregon trail route. the portion of the oregon country below the 49th parallel became part of mexico, while the portion above the 49th parallel became part of great britain.