The nervous system communicates through electrical impulses and the communication is very fast. It works in a relay fashion, from point to point comparable to the way the old telephones systems used to work.
The endocrine system communicates by chemical signals via the bloodstream. Hormones are secreted into the blood and extra cellular fluids, then transported to target cells, which must bear a receptor to be able to bind to a specific hormone, and respond.  
Hormones are chemical messengers secreted into blood or extracellular fluid that affect the function of other cells.
Endocrine communication is not quite as fast as the nervous system communication
 
        
             
        
        
        
The answer is C because the load shouldnt be greater than the effort, it isnt usually, but my best answer to you would be C 
        
             
        
        
        
Answer:
One parent was homozygous for white flowers and the other was hoozygous purple, and  Both parents had purple flowers?
Explanation:
 
        
                    
             
        
        
        
Answer: The respiratory system, the circulatory system, and the muscular system
Hope this helps :)