Which statement best completes the diagram?

How was rockefeller able to build his monopoly across the oil industry? he found newer and cheaper ways to refine oil, increasing his profits. he confined his business to ohio so he could buy all the refineries there. he bought up oil refineries, cut costs, and reinvested his profits in other refineries. he began to sell kerosene as well as oil, expanding his market.

What was the land like around rome? dry rocky fertile volcanic

How did african americans the union during the civil war? a. by serving as representatives in congress b. by enlisting in the military to fight c. by organizing massive slave revolts in the south d. by negotiating for peace with the confederacy