Answer: The answer is B while neutrons and electrons are usually the same in a given atom protons are always consistent. 
 
        
             
        
        
        
Separation of sister chromatids
        
             
        
        
        
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- To keep our oxygenated blood and our deoxygenated blood separate. 
Having 4 chambers allows these 2 types of blood to reach their appropriate destination without getting mixed up. 
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