Final answer:
Duluth, Minnesota, is the major port on Lake Superior, which was essential for iron ore shipping in the early 1900s. Chicago became a crucial transportation hub after the Illinois-Michigan Canal linked the Great Lakes and Mississippi River system, driving quick urban growth.
Step-by-step explanation:
The major port on Lake Superior is in Duluth, Minnesota. This port was historically significant for the shipping of iron ore, as illustrated by the ore docks of the Duluth, Missabe and Northern Railway that loaded ships like the George H. Russel. Duluth's port contributed to the regional economy, particularly in the early 20th century.
Meanwhile, Chicago developed into a crucial transportation hub due to its strategic location connecting the Great Lakes and Mississippi River system. The construction of the Illinois-Michigan Canal in 1848 and the arrival of multiple railroad companies bolstered its status as a major port city.
Chicago's transportation advantage propelled it into a rapid urban growth, where it became the second most populous city in just over 30 years.