Well yes, but a dichotomous key can be used to classify just about anything you want. 
Hope that helped
        
                    
             
        
        
        
A single gene could be inserted into a plant's genome, enabling specific traits to be expressed easily. Scientists have identified genes for two enzymes needed to make pro-vitamin A. One of these genes comes from corn.
        
                    
             
        
        
        
That's  true because the basic functions of a multi-cellular plant occur in the cell and like any other cell, unicellular alga are also cells thus basic functions such as respiration, excretion, growth occur in both multicellular organisms as well as unicellular organisms
        
             
        
        
        
I think it’s a Roji because it looks infested