Why did african americans work for the ranchers?

Study the graph and then complete the analysis of the data by filling in the missing information.

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.

Ineed a summary over the 6th amendment