The variable is independent because you are affecting it by changing it individually. It would be dependent if you changed one variable then the water was affected.
        
             
        
        
        
Answer:
There are a couple different possible answers, since there are multiple different structures that are present in both types of cells. So you have to make the choice of what to put. 
The structures that prokaryotic and eukaryotic cells have in common are: plasma membrane, ribosomes,  and cytoplasm
 
        
                    
             
        
        
        
If its a dominant allele 75%
if its recessive allele 25% 
thats what i was always taught i hope this helps some :)
 
        
             
        
        
        
The plants remaining would be the only plants then will come as the animals die because they cant eat plants because all the plants are gone then will come us which we will die because there aren't any animals to thrive on