Which kinds of cells are always single-celled? eukaryotes prokaryotes

Prokaryotes

Explanation:

Prokaryotic cells are the most primitive cells and lack some features as compared to the eukaryotic cells. The eukaryotic cells are actually evolved from the prokaryotes only but it contains organelles which are specific in their function for example Golgi body, Mitochondria etc.. Eukaryotic cells can be single celled or multi-cellular hence complex and large structures while prokaryotes are unicellular or single celled hence simple and small cells. Eukaryotic cells have well defined nucleus but prokaryotic cells do not have a well defined nucleus. In eukaryotes usually cell wall is absent and if present consist of cellulose while cell wall is present in prokaryotes.Example of prokaryotes includes archaea, bacteria etc and those of eukaryotes are plants and animals.

Ithink the answer is nuclear membrane