Those that do not show artificial selection are examples A and B.
        
                    
             
        
        
        
Answer and Explanation: The excretory system helps the respiratory system by getting rid of carbon dioxide. The respiratory system helps the excretory system by getting rid of CO2 from the body. They both need each other and if one or the other did not exist, we might've not been able to survive. Tis demonstrates how vital they are for the human body. 
 
        
             
        
        
        
Answer:
How is the endocrine system related to the nervous system in terms of its regulatory activity?
For one, the endocrine system uses chemical signaling (hormones, produced by glands) while the nervous system uses electrical signaling (neural impulses). The signal transmission of the nervous system is fast because neurons are interconnected, but the functions are more short-lived.
Explanation:
 
        
             
        
        
        
Pyruvic acid binds with Coenzyme A (CoA) to form acetyle CoA. The acetyle CoA begins the Kreb Cycle.