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:
The Urban Population. The factories protected by the tariff would run at a profit and employ the urban population. The city dwellers would constitute an increased market for agricultural products and would manufacture goods for use in farming regions. The farms would supply raw materials to the factories and food to a growing urban population. Clay’s American plan was rejected, but Congress was able to pass protective tariff.
Thomas Jefferson said “—That whenever any Form of Government becomes destructive of these ends, it is the right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles, and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness… it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.”
Answer:
it SHOULD be c. The compromise was meant to maintain a balance of free and slave states when new territories were added.
Explanation: