What three powers did the Steelers in the three cases listed in the chart

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.

Unique among the rulers of this time, persian emperors installed governors in their provinces tolerated local cultures and laws wielded absolute power maintained an extensive army

What is the columbian exchange? o a. the changes that resulted from europeans settling in the new world b. the relationships that columbus and his men had with the natives they met o c. the ships that columbus bought with money from the king and queen of spain o d. the increase in the number of native american towns in the new world