Final answer:
The rapid expansion of urban areas was a major result of both immigration and the increased productivity of factory jobs in the late 1800s. This led to a major demographic shift as workers congregated in cities to meet labor demands, with immigrants significantly contributing to urban population growth.
Step-by-step explanation:
The major result of both immigration and the increased productivity of factory jobs in the late 1800s was A. The rapid expansion of urban areas. As technological advances and greater factory efficiency drove the demand for labor, workers, including many immigrants, were attracted to cities for employment opportunities. This movement led to a significant shift in population dynamics, with individuals leaving rural areas and agrarian lifestyles in favor of industrial work in urban environments. Concurrently, increasing numbers of immigrants arriving in the United States added to the already swelling urban populations.
During this period, urban centers expanded quickly due to these demographic changes. These burgeoning cities offered the promise of employment, but they also required factory workers to live nearby due to demanding work schedules. Furthermore, as innovations like commercial electricity emerged towards the end of the century, industries migrated into urban areas, establishing cities as economic hubs. By 1920, half of the nation's population resided in urban areas, a stark contrast to the predominantly rural America of 1880.
The influx of immigrants contributed to the diversity and cultural richness of these expanding cities. Although they initially viewed their stay in the cities as transient, their presence and labor fundamentally shaped the American urban landscape during this transformative era of industrial growth.