American History Part 2 Grade 8
With the Westward Expansion and growth in population and resources comes an explosion of industrial activity. The railroads had the largest, lumber, steel and coal created the most economic opportunity. The cities grew also with immigrant populations, the need for workers in factories caused overcrowding  in tenements. Economic growth brought social inequalities.
Inventions of the late 1800's and early 1900's revolutionized the landscape of America.