Carnegie turned his one Pennsylvanian production plant into a veritable steel empire through a business tactic called vertical integration.
Explanation:
Andrew Carnegie was a Scottish-American industrialist and philanthropist. Carnegie led the expansion of the American steel industry in the late 19th century and became one of the richest Americans in history. He became a leading philanthropist in the United States and in the British Empire.
Hope this helps! If so please mark be the brainliest! Peace and love
