First one is the correct answer
Cause--Effect:
Passage of the Homestead Act-- allowed many families to purchase land cheaply and set up farms.
Creation of agricultural technology-- new machines such as tractors, plows, and harvesters created greater output at a faster, more efficient pace.
Indian Wars-- the last of the Indian Wars took place on the Plains following the Civil War. By clearing the land and putting the last remaining tribes in reservations, land was available for farming.
