Prokaryotes are characterized by:

Ans. is 'a' i.e., Absence of nuclear membrane(Ref: Ananthanarayan, 9th/e, p. 10 and 8th/e, p. 10, 13)ProkaryotesEukaryotesNuclear membrane absentNuclear membrane well definedCytoplasmic structures absent, e.g., Mitochondria, Lysosomes, Golgi apparatus, and endoplasmic reticulum are absent.All these cell organelles are presentIn cell wall muramic acid and diaminopimelic acids (DAPA) presentBoth absent in cell wallNo sterols in cell membraneSterols present in cell membraneE.g.: Bacteria, blue-green algaeFungi, protozoa, slime mouldsSite of respiration - MesosomesMitochondria