How did the berlin blockade hurt the west berliners

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.

Why did river valleys most farming impact the lives of neolithic peoples?

What did nativists think about chinatowns in the late 1800s?