Nuclear arms race was a key factor in extending the time period of the cold war. The seeds of the hostility between USSR in US began after the end of World War I with the rising of communism in USSR in Stalin rule made it worse.
        
             
        
        
        
A. Government provides services that would not be practical for private business
        
             
        
        
        
The issue of slavery was a major underlying issue to the formation of the Republican party.
On May 20th, 1854,  a group of politically- minded former Whigs met in Ripon , Wisconsin to talk about the possibility of forming a new political party that would focus on preventing the spread of slavery in the Western territories. The idea  took off and on June 6th 1854, over 10,000 people  gathered in Jackson, Michigan to establish the new party and thus the Republican party was born.
 
        
             
        
        
        
Trains from different rail lines could use each other’s tracks