Which event resulted directly from the growth of railroads in the 19th century?

Beginning in the early 1870s, railroad construction in the United States increased dramatically. ... Between 1871 and 1900, another 170,000 miles were added to the nation's growing railroad system. Much of the growth can be attributed to the building of the transcontinental railroads.

Explanation:

The Civil War was the defining event for nineteenth-century America, and railroads played an important role in the conflict. As the North industrialized rapidly between 1820 and 1860, railroads helped create --and prospered from -- the rise of factory production and diversified large-scale agriculture.

as general terms,  indian territory,  the indian territories, or  indian country  describe an evolving land area set aside by the  united states government  for the relocation of  native americans  who held  aboriginal title  to their land. in general, the tribes ceded land they occupied in exchange for  land grants  in 1803. the concept of an indian territory was an outcome of the 18th- and 19th-century policy of  indian removal. after the  civil war(1861–1865), the policy of the government was one of  assimilation.

what are the choices?