The circulation of water in the ocean due to
differences in density between the different layers of water is most
likely responsible for "<span>B deep water ocean currents" The moon is responsible for the tides, and under water volcanoes will erupt regardless of the water density. 
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 x or y because both can cause it 
 
        
             
        
        
        
Answer:
any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in the nucleus, or different atomic weights. There are 275 isotopes of the 81 stable elements, in addition to over 800 radioactive isotopes, and every element has known isotopic forms. Isotopes of a single element possess almost identical properties.
Explanation:
 
        
                    
             
        
        
        
The answer is B. molecule, I know becuase I just took the test and got 100%  Hope it helps