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:
There are many moral standings and ideals that existed in the last that are completely at odds with what we think today. Or there were ideas on face and science that are just completely strange in comparison with today's ideas. Primary resources don't show a complete picture, because there are always gaps that need to be filled along the way. For example, a lot of primary sources and writing for Viking cultures were written by Christian writers, so it doesn't offered a clear perspective on the pagan side.
Because they thought that it would better their new life there in the new world known a as America
An uprising of most of the Pueblo<span> Indians against the Spanish colonizers </span>
it would be c because Lewis was a chairman for that organization.
