How is it that crop yields increased in the decades after world war ii despite the number of farms decreasing? a. the growth of bio-engineering proceeded new types of high-yield crops. b. cotton began to replace corn as the united states' main agricultural export. c. mechanization decreased the number of farmers needed to work land. d. demand for u. s. crops forced more efficient use of existing farmland.

"the plan of removing the aboriginal people who yet remain within the settled portions of the united states . . approaches its consummation. . an extensive region . . has been assigned for their permanent residence. it has been divided into districts and allotted among them. many have already removed and others are preparing to go. . " removal of southern indians to indian territory, 1835 this passage is most closely related to a) imperialism. b) the civil war. c) westward expansion. d) the french indian war.