"There were 2 main reasons: 
<span>The Second Industrial Revolution created the need for a workforce in new factories,so many people moved from the countryside to the cities to find jobs in these factories.The effects of the depression of 1873-1896,which spread to America,further encouraged people to go to the cities to find work. </span>
<span>There was a long economic depression in Europe from 1873-1896,which encouraged many Europeans to emigrate to America.Most of these arrived at major port cities,and found jobs in factories so stayed there.</span>
        
             
        
        
        
Most of them were overthrown by 750 B.C.
        
             
        
        
        
The period between the end of the middle ages and the present 
(apex)
        
             
        
        
        
Answer:
Examples of a secondary source are: Publications such as textbooks, magazine articles, book reviews, commentaries, encyclopedias, almanacs.