How did the ever-increasing presence of the railroads change life in the United States during the period of 1880-1920?

Explanation:

The presence and expansion of the railroad brought many advantages to the US. Among many, we could cite the fact that it made the western US more important nationwide. Before, the east coast it was not only the main country hub but also regarded as the only civilized one. Railroad facilitated the transportation of people, infrastructure and cargo to the west. That transportation made travel to that part of the country more affordable to people, increasing the west population, as well as increased economic relations between the east coast and the rest of the country. However, due to entering wild areas and in need of a high amount of wood to be made, It brought as well a high impact in the environment and increased racial conflicts with locals.  

a is the final ! : )