<span>People in north refused to allow escaped slaves to live in their states
For the north states were against slavery, and known as 'Free states'
hope this helps</span>
While you didn't really provide the "following" as the comment above me states, in general, the advantage of secondary sources of primary ones is that they perhaps provide a more objective or even just a broader view on a certain topic. While a primary source of the American civil war would be a letter written by a soldier, a secondary source would be a book that describes more letters taken together and discusses possible information regarding them.
Answer:
He constructed The Royal Road and expamded trade
Explanation:
