Final answer:
The rise of industrialization in the United States between 1865-1900 chiefly led to the formation of unions that advocated for better worker wages and conditions.
Step-by-step explanation:
Industrialization in the United States during 1865-1900 spurred the rise of unions to demand better wages and conditions for workers. During this era, the country saw a dramatic transformation from an agrarian economy to an industrial economy.
The vast wealth created through industrialization led to social and economic disparities. Entrepreneurs like Andrew Carnegie and John D. Rockefeller built large empires, changing the American landscape.
However, this also resulted in the exploitation of workers, which in turn fostered the formation of labor unions. These organizations played a critical role in improving the conditions for workers, leading to social reforms and the start of regulations that would be more fully realized in the 20th century.