Answer:
Soon, soldiers and civilians began using the nickname Uncle Sam to refer to the United States.
Explanation:
Sentences 11 and 12 are both talking about "using the nickname Uncle Sam to refer to the United States".
In sentence 11, it talks about soldiers. In sentence 12, it talks about civilians.
You can say:
Soon, soldiers and civilians began using the nickname Uncle Sam to refer to the United States.
 
        
             
        
        
        
It’s a phrase because it doesn’t have a subject
        
             
        
        
        
Giving human characteristics to object, places, or things 
Ex: The paper danced across the classroom
        
                    
             
        
        
        
Swimming is a good sport it helps build muscle.