Final answer:
The two industries dominated by Andrew Carnegie and John D. Rockefeller were the steel and oil refining industries, respectively. Carnegie utilized vertical integration and the Bessemer Process to outperform competitors, while Rockefeller controlled vast portions of the oil industry, setting the stage for corporate monopolies.
Step-by-step explanation:
Andrew Carnegie and John D. Rockefeller were two titans of American industry who dominated the steel and oil refining industries, respectively. Carnegie implemented the Bessemer Process at his Pittsburgh-based Carnegie Steel Factory, leading to his control of the US steel market by 1900. Through vertical integration, which involved owning all parts of the production process, he significantly cut costs and ensured a high-quality product, outperforming British steel production.
Rockefeller, through his company Standard Oil, controlled an astounding 90% of the nation's oil refineries by strategically integrating every stage of the oil business. He made aggressive moves such as demanding discounts from suppliers, and his competitors could not contest his size and power, leading to Standard Oil’s domination. Their businesses thrived, influencing other industrialists to create trusts and monopolize various sectors of the American economy.