One of the main things that the United States <span>learned during the space race was that Russia was a very formidable opponent, and that it was extremely expensive and time-consuming to send things into space--especially humans. </span>
        
             
        
        
        
Racism and sexism came hand and hand but if anything classism seems like the first where royalty or nobility would look down on people with lower social status like peasants.
        
                    
             
        
        
        
The correct answer is B. In  Nassau County, New York
Explanation:
The word "Levittown" refers to different massive suburbs that were created after the World War in the U.S. and Puerto Rico and that were called "Levittown" because these suburban developments were created by the company Levitt & Sons. The objective of these suburban areas was to prove an alternative to cities especially to those that return from the war and their families. The first Levittown was built in New York in Nassau County, Long Island between 1947 and 1947 and this was followed by a Levittown in Pennsylvania (1952), New Jersey (1958) and later Puerto Rico (1963). Therefore, it can be concluded the first Levittown was built in Nassau County, New York. 
 
        
                    
             
        
        
        
Correct answer choice is :
D) To act as a ceremonial role within the Senate.
Explanation:
The President pro tempore of the United States Senate is the second leading ranking leader of the United States Senate. Article One, Section Three of the United States Constitution renders that the Vice President of the United States is the President of the Senate, and mandates that the Senate must elect a President pro tempore to act in the Vice President's inadequacy. Unlike the Vice President, the President pro tempore is an elected member of the Senate, ready to express or vote on any matter. Elected by the Senate at large, the President pro tempore has experienced many events and some short commands. During the Vice President's inadequacy, the President pro tempore is authorized to control over Senate gatherings.
 
        
                    
             
        
        
        
The correct answer is D, domestication of animals. All other alternatives refer to events that only happened later. 
In order to affirm an Agricultural Revolution ocurred, historians have to choose the most important changes and events that determine that from that moment onwards life was different. 
The most important thing that supports the idea of an Agricultural Revolution is that humans started to domesticate plants and animals, which made possible for them to settle and stop being nomads. 
This lead to the birth of cities and to radically change how those people lived.