Final answer:
John D. Rockefeller amassed wealth in the oil industry, Andrew Carnegie in steel production, and J.P. Morgan in finance and banking; these individuals dramatically impacted the economy during the Gilded Age.
Step-by-step explanation:
The three extremely wealthy Americans during the Gilded Age who made extreme amounts of money and their respective industries are John D. Rockefeller - Made his fortune in the oil industry, fundamentally changing it with innovative refining techniques.Andrew Carnegie - Dominated the steel industry, establishing a vast empire that revolutionized how steel production impacted industrial growth.J.P. Morgan - Influential in finance and banking, he helped finance the consolidation of industries and negotiated the creation of major corporations.These titans of industry not only amassed great fortunes but also ushered in a new economic landscape by exploiting advancements in technology and refining business practices. Their companies' growth changed the American way of life, contributed to urbanization, and they played a significant role in shaping modern America.