Respuesta :
The correct answer is A, as the construction of railroads connecting Northeastern cities and Midwestern farms was the factor that made population increase greatly in Chicago.
With the development of the railroad and the Illinois and Michigan Canal (in 1848 the Illinois and Michigan canals were built, interconnecting the Great Lakes with the Mississippi River), Chicago became leader in the cattle, wood shavings, wood industry and wheat production. Word spread that the city was full of opportunities, and by the mid-1850s, up to one hundred thousand immigrants arrived annually in the city, looking for land and work.
The factor that best explains the population change is the construction of railroads connecting Northeastern cities and Midwestern farms.
With the development of the railroad, Chicago became leader in the cattle, wood shavings, wood industry and wheat production.
Hence, the factor that best explains the population change is the construction of railroads connecting Northeastern cities and Midwestern farms was the factor that made population increase greatly in Chicago.
Therefore, the Option A is correct.
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