Answer:
Oceans, lakes, any large bodies of water.
Explanation:
In terms of country populations, oceans separate the different populations from each other.
 
        
             
        
        
        
Your brain stem would be your answer
        
             
        
        
        
Okay what u want me to help you with
        
                    
             
        
        
        
The nucleus will have the greatest mass. Among the 3 kinds of subatomic particles, electrons are the lightest (by several orders of magnitude), protons and neutrons are much closer is magnitude, though neutrons are slightly heavier. However, in the diagram, the nucleus contains both the neutrons and the protons, so its combined mass would be heavier than either the neutrons alone or the protons alone.