Parliamentary systems usually have a head of government and a head of state.The head of government is the prime minister who has the real power.The head of state often is an elected either popular or through parliament president or in case of a constitutional monarchy hereditary. 
        
             
        
        
        
The titular head of a nation as distinct from the head of the government.
        
             
        
        
        
Answer: Vygotsky's theory of cognitive development 
Explanation: Vygotsky's Cognitive Development Theory is the theory that states about the constructive behavior of the children to obtain the cognitive  factors. Instruction ,guidance and interaction on social base is considered as the feature of the theory which enhances the learning , solving problem and other skills.
The situation mentioned in the question describes about the Vygotsky's theory because Dr Smith believes in improving the knowledge through instruction in 9-year old .
 
        
             
        
        
        
The responsibilities of the executive branch include: carrying out and enforcing laws made by congress, the President has to pass or veto laws, carry out day to day operation of government.
        
             
        
        
        
Area formula for a circle is pi *r^2
circumference is pi * d 
22.6/3.14 is 7.197= diameter 
radius= 3.5985
pi * (3.5985)^2 =40.66
area is about 40.66 square inches