Respuesta :
Answer - D. Prokaryotes are only single-celled.
Reasoning - Reason why they are single-celled are unicellular is because they do not have a bound nucleus membrane.
Reasoning - Reason why they are single-celled are unicellular is because they do not have a bound nucleus membrane.

Answer: Option D
Explanation:
Prokaryotes are single celled organism. They do not have membrane bound organelles. They have their nucleus dissolved in the cytoplasm.
The most primitive organism are prokaryotes as they do not have membrane bound organelles in it it has a smaller size as compared to that of eukaryotes.
Eukaryotes are advanced type of organism that is multicellular and have distinct organelles.