USA HISTORY

Detailed explanation-1: -A large workforce was available due to 1) a huge influx of immigrants, which caused the U.S. population to triple between 1860 and 1910, and 2) increased migration to the cities from southern farms, where mechanization was decreasing the need for labor.

Detailed explanation-2: -Millions moved from the countryside and overseas to become city dwellers; the urban population grew from 6 million to 44 million between 1860 and 1910. A steadily rising number of migrants from southern and eastern Europe-Italy, Poland, Russia-settled in the cities.

Detailed explanation-3: -Between 1860 and 1910, the population of the United States almost tripled. This population provided industry with a large workforce and also created greater demand for the consumer goods that factories produced. Population growth stemmed from two causes-large families and a flood of immigrants.

Detailed explanation-4: -Others came seeking personal freedom or relief from political and religious persecution, and nearly 12 million immigrants arrived in the United States between 1870 and 1900.