The cerebrum controls the higher brain functions such as speech, writing, etc. The cerebellum deals with the involuntary stuff. The other 2 are nowhere near what you are looking for.              B - Cerebrum is your answer.
 
        
             
        
        
        
The answer is A. Excretion I hope this helps 
        
             
        
        
        
They are both are types of explanations.
        
                    
             
        
        
        
The answer is C. The Experiment!!!!! 
        
                    
             
        
        
        
Answer:
For effect #1, the mutation will become more common (A). This is because with the organism having more children, the trait will be passed around much faster and will spread to surrounding groups of animals. 
For effect #2, the mutation will become more common (A). This is because the disease will kill the animals who do not carry the gene leaving only the animals with the trait, making it much more common
For effet #3, the mutation will disappear (B). This is because the animal carrying the gene will slowly die off. After all,  they will not be able to reproduce and pass the gene to their children. 
For effect #4, the mutation will remain at a low level (C). This happens because since it procures no change there will be no reason to transfer it so it will become a recessive trait in the animals. 
Explanation:
Hope this helps. . . <3