What did carneige use to integration to form his monopoly

He created the monopoly by gaining control of all levels of production of steel

Explanation:

Oil was among the many commodities that had a high demand during the age of Gilded, and the nation also had a high demand for steel. It is, therefore, because of this, that Gilded used the scenario and was in control of all the steel industry in America. Each sector in American was in dire need of steel for machinery with physical plant. Because of this scenario, Gilded saw the opportunity and used the opportunity to exploit them.