In which of the six essential elements of geography would you study instances of cooperation and conflict in populations? a. human systems b. location c. human-environment interaction d. movement

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.