Final answer:
The characteristics most associated with the Gilded Age include the factory system and the growth of the railroad industry, marking an era of industrialization and urbanization.
Step-by-step explanation:
The characteristics that are most associated with the Gilded Age are factory system and the growth of the railroad industry. During this era, America saw a significant transformation from a rural country to urban centers due to the expansion of industrial factories fueled by an increasing workforce from the large immigration wave.
The extensive development of railroads played a crucial role in connecting different parts of the country and facilitating the movement of goods and resources, which defined the industrial landscape of the time. Moreover, factories during the Gilded Age were often dangerous and unsanitary places, where workers faced long hours and low pay, which led to the organization and growth of labor unions.