What is the main difference between a cell nucleus and a nucleoid?
A.
size of the organelle
B.
arrangement of the cytoskeleton
C.
movement of the flagella
D.
presence or absence of a surrounding membrane

Question

What is the main difference between a cell nucleus and a nucleoid?  
  A. 
  size of the organelle   
  B. 
  arrangement of the cytoskeleton   
  C. 
  movement of the flagella   
  D. 
  presence or absence of a surrounding membrane

anonymous · Answer

I'll  go with D thus, from what I recall, a nucleoli can exist without a surrounding protective membrane because it's simply the region of concentrated genetic material aggregations. (Correct me if I'm wrong on that.) While a nucleus is an actual essential organelle found in particular Eukaryota organismal cells.