They moved out of the foothills and into the plains (near rivers). The rivers provided more opportunities for food growth.
They were too large and expensive - typically a computer would fill a room and would have to have its own power supply.
Answer:
a
Explanation:
First continental congress
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:
