USA HISTORY

Detailed explanation-1: -In 1848 Chicago got its first telegraph and railroad. Two innovations-grain elevators and the Board of Trade’s wheat grading standards-quickly transformed the way crops were sold. By 1854 the city was the world’s largest grain port and had more than 30, 000 residents, many of them European immigrants.

Detailed explanation-2: -The manufacture of electrical and communications goods made Chicago the Silicon Valley of its day. While its traditional trading function did not disappear, the city was also transformed into the national epicenter of the commodities trading and mail-order industries.