Which statements are true about the expansion of the united states between 1789 and 1850? choose all answers that are correct. a. a belief in manifest destiny was a major reason that the united states went to war with mexico. b. by 1850, the boundaries of the united states stretched from the atlantic to the pacific. c. by 1820, the united states had still not acquired any territory west of the mississippi. d. the united states tried to annex the independent republic of texas, but its citizens refused.