Answer: Hydroelectricity.
Explanation:
 
        
                    
             
        
        
        
Answer:
the expanse of salt water that covers most of the earth's
 
        
                    
             
        
        
        
During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's  atmosphere had no free oxygen then. This is about 3.5 billion years ago.
        
             
        
        
        
Answer:
Ranching and live stock are located in the fourth ring because animals can be raised far from the city because they are self-transporting—they can walk to the central city for sale or for butchering.
Explanation:
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Answer:
Correct answer is D: natural law.
Explanation:
D is correct answer as it is an idea that spread during the period of Enlightenment. It was used by John Locke, but also later by Thomas Jefferson.
A and B are not correct as this are forms of government inside which certain group of individuals controls everything.
C is not correct as limited government is also a form of political system.