How was rockefeller able to build his monopoly across the oil industry

Buying rival refineries

Explanation: American industrialist John D. Rockefeller was born July 8, 1839, in Richford, New York. He built his first oil refinery near Cleveland and in 1870 incorporated the Standard Oil Company. By 1882 he had a near-monopoly of the oil business in the U.S., but his business practices led to the passing of antitrust laws.

Standard Oil gained a monopoly in the oil industry by buying rival refineries and developing companies for distributing and marketing its products around the globe.

d.prevent the spread of communism outside of eastern europe.

they move troops weapons suplies food water shelter vehicles ect. hope this : 3