Which structure is unique to eukaryotic cells?

a. DNA

b. cell membrane

c. ribosomes

d. nucleus

The answers D. Nucleus because both Eukaryotic and Prokaryotic cells have DNA (its circular in PK and Linear in EK).

Both cells have ribosomes and both have a cell membrane. However Prokaryotic does not have a nucleus and only Nucleoid DNA.

The blue wiggle is the nucleoid DNA, and the red dots are ribosomes