How did technology lend to geography expansion and growth of cities in the 1800s in the United States?

The rapid expansion of big business, the development of large-scale agriculture, and ... An outburst of technological innovation in the late 19th century fueled this ... making the United States the world's premier food producer--a position it has ... This led to wars against the Native Americans of the Plains.

the united states didn't wanted to get involve with other countries probelms

i am pretty sure the awsers is d.