Answer:In 1947, Salk took a position at University of Pittsburgh, where he began conducting research on polio, also known as infantile paralysis. By 1951, Salk had determined that there were three distinct types of polio viruses and was able to develop a "killed virus" vaccine for the disease.
Explanation:
Well, from among the choices given your answer is going to be B. This is because the British had been taxing people and taking tea and selling it. So everyone threw it overboard as a sign of rebellion.
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<span>Napoleon failed to conquer Russia in 1812 for several reasons: faulty logistics, poor discipline, disease, and not the least, the weather. Napoleon's method of warfare was based on rapid concentration of his forces at a key place to destroy his enemy. This boiled down to moving his men as fast as possible to the place they were needed the most. To do this Napoleon would advance his army along several avenues and converging them only when necessary. The slowest part of any army at the time was the supply trains. While a soldier could march 15 - 20 miles a day, a supply wagon was generally limited to about 10 - 12 miles a day. To avoid being slowed down by the trains, Napoleon insisted that his troops live as much as possible off the land. The success of Napoleon time after time in Central Europe against the Prussians and the Austrians proved that his method of warfare worked. However for it to work, the terrain must co-operate. There must be a good road network for his army to advance along several axes and an agricultural base capable of supporting the foraging soldiers.</span>
C. Market conditions and the invention of the cotton gin
Government was pro corporations and the labor unions was non vilont and did not seek violence
