If we start to travel from the Mississippi River westwards to the Pacific Coast, than the starting point is a lowland, vast one, as we continue to go towards the west we will encounter high mountains, the Rocky Mountains more specifically, and the elevation will go up to 4,400 meters above sea level, than we will go down, elevation wise, to the high plateaus and will be on elevations between 1,000 and 2,000 meters, and after we go up again to almost 4,400 meters as we cross the Cascade Mountains. After the Cascades we go gradually downwards towards the lowlands, where we will first go a bit bellow sea level, and than little up in the lowlands along the Pacific Coast, and at the end reach a point of zero elevation.
the english introduced horses into the new world
I think its D: The Red Sea
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.
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