<span>When examining how Rockefeller became successful, notice that he owned absolutely everything regarding the production and transportation. This means that the answer is C) Combined vertical and horizontal integration. He became a monopoly owner meaning he owned everything regarding the production of oil and didn't rely on anyone.</span><span />
It was known as the Colombian exchange
He was a leader who worked for the wellfare of the masses
The Union used a large naval blockade to stop most of the South's cotton trade. I hope this helps!