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:
Answer:
The answer is A, He is 24 years old.
Explanation:
The law states that the legal age requirement is to be at least 25 or older. Hope this helps :)
John Hancock and also John Adams
<span>Answer is B. Most peasants had been freed from serfdom and were improving their economic situation.</span>
In his text "Slavery, a System of Inherent Cruelty," Theodore D. Weld shows how cattle were sometimes treated better than slaves. An example he gives of this is how cattle are allowed to graze as much as they want, while slaves often received a very small portion of food. Another example he gives is how when cattle are to be sold, they are transported in a way that is comfortable to them. On the other hand, slaves often had to walk very long distances, regardless of the weather, while being chained to each other.
