Answer:B, D
Explanation:
When the roller coaster starts flying down the hill, it gains kinetic energy and loses potential energy.
 
        
             
        
        
        
<span>A warm front is the boundary between a warm air mass and a cold air mass it is overtaking. So a cold front would be the opposite. 
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Answer:
D
Explanation:
They would be dying off, or leaving to get away from the disease 
 
        
                    
             
        
        
        
Answer:
Calculate the age of an object by finding how much carbon-14 remains in the sample