The dust bowl was a sever drought caused by fluctuations in ocean temperatures. Other factors that contributed to the affect it had on the Midwest was the dry climate and their use of poor farming techniques.
The south improvement company in 1872 caused rockefeller able to monopolized around 90% of the oil market in North America.
The south improvement company largely increased the number of oil and railroad companies in southern states. Because of the increase in numbers, the market for oil and railroad companies became saturated. This lead many of his competitors to bankruptcy, which is why the competitors called it a conspiracy.
Answer: Most likely the industrial revolution.
Explanation: The use of machines in production became more and more prevalent, eventually many factories were built in cities which caused pollution therefore making the air gross.
It was mainly developments in the "steel" industry that made important contributions to improvements in the transportation system in the United States during this time, since the major advancement in transportation was in the railroads, which were made from steel.
