Answer:
Through vertical integration
Step-by-step explanation:
Andrew Carnegie, during the industrialization in America, was able to make his steel company more efficient due to combining many companies into his. After investing in railroad and oil, he decided to build the Steel industry with partnerships of many industrialists in America. The connections with Henry Clay Frick, George Lauder, and Thomas M. Carnegie, led Andrew Carnegie to buy several small steel mills in Pittsburgh. The alliance of the several companies including the Homestead Steel Works and mills led in the establishment of the Carnegie Steel Company in 1892.