Read the information below:

in 1840, the population of chicago was only 4,470. by 1900, the city's population was 1,698,575.

which factor best explains the population change?

a. the construction of railroads connecting northeastern cities and midwestern farms

b. the reduction in immigration quotas on southern and eastern europe

c. the spread of government housing for low-income workers throughout u. s. cities

d. the successes of the settlement house movement

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.