Because  some scientist might see something that other scientist do not. good luck.
        
                    
             
        
        
        
That would be a Chloroplast
 
        
                    
             
        
        
        
Internal means its on the inside 
external means its on the outside 
so an internal regulator is when the proteins respond to events on the inside of a cell 
and an external regulator is when the proteins respond to events outside the cell
        
                    
             
        
        
        
Answer:
is there suppose to be a pic?
Explanation: