Answer:
This is called cluster sampling procedure.
Explanation:
In this type of procedure, a group of elements is considered instead of individual units. This proceddure is usually based on geography, and it's useful due to its efficiency regarding cost and time. 
There are a few disadvantages, though: it might not be diverse enough to be significant, and it's possible that some elements of other groups (in this case, other districts) share some features. 
 
        
             
        
        
        
Answer:
A.) The Cuban Revolution 
Explanation:
July 26, 1953, Fidel Castro and his allies went against the military dictatorship  of the Cuban president Fulgencio Batista.
 
        
                    
             
        
        
        
Answer:
It's a policy of extending a country's power and influence through diplomacy or military force.
 
        
                    
             
        
        
        
<span>Preschool programs are called “child centered” when they stress children’s development and growth. The “child centered” philosophy is also often called “play based.” Children in this type of program are allowed to choose to participate in activities that match their current interests, such as playing house or building with blocks. Teachers encourage the children to play, and through playing they learn important social skills.</span>
        
             
        
        
        
Answer:
In my opinion,  they didn't.
Explanation:
The "Indian Removal" refers to a time period when a lot of native American people were forced to get out from their ancestral homes. The reason for this was because the US government wanted to obtain control over the natural resources that exist within these lands. In return, they gave the Native American people with a set of land that they called "Reservation".
But, the value of the reservation land was nothing compared to the value of the land that was taken away from them. (Both from cultural and economic point of view). This action prevented the Native American community to develop their community and massively reduced their social influence in United States.