There are thousands of bacterial species and they are not identical towards one another, therefore there forms are quite unique. so its just there characteristics that make up how bacteria look like.
Hope this answers your question. 
 
        
        
        
It will be transported into the cell through the process of endocytosis, which is a form of active transport. Active transport requires energy in the form of ATP. Hope this helps! :)
        
             
        
        
        
The system of classification relates to the diversity of species because the system of classification is how we organize the diversity of species. With out it we would have a hard time trying to determine which animals belong with which group. There would be no order, just chaos of trying to determine animal likeness of one another. 
To cut this answer short, it helps them organize organisms.