The main difference between prokaryotic and eukaryotic cells is that A. prokaryotic cells are always much larger. B. prokaryotic cells do not have a plasma membrane. C. eukaryotic cells have a smaller cell nucleus. D. eukaryotic cells have a more complex cellular organization.

Correct answer is d (eukaryotic cells have a more complex cellular organization) . 

Explanation: Prokaryotic cells and eukaryotic cells are the two types of cells that exist on Earth. There are several differences between the two, but the biggest distinction between them is that eukaryotic cells have a distinct nucleus containing the cell's genetic material, while prokaryotic cells don't have a nucleus and have free-floating genetic material instead.  

 The primary distinction between these two types of organisms is that eukaryotic cells have a membrane-bound nucleus and prokaryotic cells do not. The nucleus is where eukaryotes store their genetic information. In prokaryotes, DNA is bundled together in the nucleoid region, but it is not stored within a membrane-bound nucleus.

The nucleus is only one of many membrane-bound organelles in eukaryotes. Prokaryotes, on the other hand, have no membrane-bound organelles.