Answer:
D
Explanation:President Woodrow wanted peace
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:
May I see the answers you can choose from? This is likely to be a multiple choice question, and I can't help without knowing the full question.
The nullification crisis was a dispute over the power of the states to reject unconstitutional federal laws.