An apple on top of a tree it possess highest potential energy
 
        
             
        
        
        
Note about the question:
I failed to find the complete question, but I am going to give two possible options about the Punnett square that might be useful. In any of the cases, the answer is the same.
Answer:
The children´s genotype is heterozygous for the freckles trait, Ff.
Explanation:
Due to technical problems, you will find the complete explanation in the attached files.
 
        
             
        
        
        
The cell wall controls this
        
             
        
        
        
Phase 1: Starts with the separation between populations. Separated populations become adapted to local conditions and become genetically differentiated over time.
Phase 2: Genetic isolation is completed, reproductive isolation develops mostly in the forms of prezygotic RIMs. 
        
                    
             
        
        
        
B is the correct answer because none of this that you put are testable.