Answer:
D. Black Holes
Explanation:
Black holes are large objects that form dense gravity wells in space. Their gravitational pull is so strong that even light cannot escape it. 
 
        
                    
             
        
        
        
Answer:
orbital 
Explanation:
electrons are found in an orbital 
 
        
             
        
        
        
The answer is D, because gems are usually not mettallic
        
                    
             
        
        
        
Answer:
mgh is the formula for potential energy