includes the brain and spinal cord
 
        
                    
             
        
        
        
Through analysis of ice cores, scientists learn about glacial-interglacial cycles, changing atmospheric carbon dioxide levels, and climate stability over the last 10,000 years. Many ice cores have been drilled in Antarctica.
        
             
        
        
        
The variety of all life forms on Earth.
        
             
        
        
        
Explanation:
 dependent is what ur measuring, independent is the diff salt concetration 
and the control group is what stays the same like the water or the plant. not sure, it's not rlly clear