The question is asking the determine the role that the United States do in the ecosystem base on the passage and situation in the question that you have state, base on my research, I would say that its role is a Dominant. I hope you are satisfied with my answer and feel free to ask for more if you have question and further clarification 
        
             
        
        
        
Answer:
mitochondria, ribosomes, and vacuoles
Explanation:
chloroplasts and cell walls are only found in plants . 
though rare, vacuoles are found in animal cells as well as plants .
mitochondria and ribosomes are in both types of cells .
 
        
                    
             
        
        
        
Answer:
Natural forces don’t have a strong effect on recent global temperatures. The natural forces line begins to drop around 1950 and does not track with the observed temperature line. On the other hand, the human effects line rises upward with the observed temperatures, so it’s a stronger effect. Solar radiation falls into the category of natural forces.
Explanation: This is the exact answer so I recommend changing it up a little bit. :)
 
        
                    
             
        
        
        
I believe it is D bcuz there is no more reproducing of that species so it will eventually die out.                                  
        
                    
             
        
        
        
There are 3 main factors: reduced sediment flow from the Mississippi, subsidence, and sea-level rise