Question 1: Option C: The Steel Industry.
After the discovery of the abundant iron ore deposits around Lake Superior, the coal veins of Pennsylvania, and the cheap water transportation routes on the Great Lakes, American steel industries established as the largest producers in the world.
By 1910, US Steel and Bethlehem Steel were the largest in the world and Steel remained as the foundation of the American Economy, way after World War II, reaching its production peak in 1969.
Question 2: Option B: Colorado, the Dakotas, and other territories became states.
The construction of major railroads like the Northern Pacific Railway in 1864 was fundamental in the increase of settlers that arrived from western territories (mainly immigrants from northern and western Europe).
This event was key to the statehood of the Dakotas, Colorado (with the transcontinental railroad it provided the population influx that needed to save the territory and impulse the statehood movement) and other territories.
Question 3: Option B: Railroads provided jobs, brought immigrant settlers, and connected markets.
The development of the vast, cross-country railroad system through the 1800's created multiple job opportunities for many immigrants, while it also made it easier for settlers from eastern parts of the country (Europeans and Chinese people) to establish themselves in western territories across the US.
Additionally, it became a transportation network that was fundamental to the American economy, by connecting markets and industries from distant states.
