Correct Answer: D
Explanation:
Classifying organisms on the basis of whether their cells have respective prokaryotic or eukaryotic structures is invalid. This is a poor taxonomic character because two of the now accepted domains, Archaea and Bacteria, both comprise prokaryotic cells. The major lipids of archaea are branched polyprenyl glycerol esters, while those of bacteria are phosphoacylglycerols. The molecular biologies of eucarya and bacteria have some resemblances. However, it is the archaea and eucarya that are more closely related. The last universal common ancestor most probably did not have a nucleus nor organelles and therefore could be described as a primitive prokaryotic cell.