What were two effects of the louisiana purchase on the united states? a. it led to a westward migration of people looking for new lands to farm. b. it encouraged the growth of industries in areas east of the rocky mountains. c. it led to the growth of us trade along the mississippi waterway. d. it ensured a lasting peace between the united states and great britain. e. it led to an eastward migration of american indians from the newly added lands.