Because sometimes it happens that they discover a dwarf planet 
that nobody ever knew about before.  When that happens, they 
ADD the new one to the list of known dwarf planets, and then the 
total number of dwarf planets on the list increases by 1 .
        
             
        
        
        
Answer: 
Explanation:
The angular diameter  of a spherical object is given by the following formula:
 of a spherical object is given by the following formula:

Where:
 is the actual diameter
 is the actual diameter
 is the distance to the spherical object
 is the distance to the spherical object
Hence:

 This is the angular diameter
 This is the angular diameter
 
        
             
        
        
        
D. a membrane bound nucleus , lmk if im right