The prokaryotic genetic system contains A. DNA & histones B. RNA & histones C. Either DNA or histones D. DNA but no histones
Hint: Prokaryotic cells are mostly unicellular organisms, when it comes to the genetic system, they differ from the eukaryotes by lack of a true nucleus and the nuclear membrane is absent and it is simply named as the nucleoid.
Complete answer: According to the study of the origin of life, prokaryotes are formed before the eukaryotes. Prokaryotes lack most of the cell organelles that present in the eukaryotes. Prokaryote has the cytoskeleton which is more primitive than the eukaryotic cell structure. When coming to the other cell structure, flagella are present in most of the prokaryotes as locomotory organs. The cell wall is present in some genera, which protects the cell and gives shape to organisms, and the cell membrane also present which covers all the cytoplasmic structures and helpful for in and out movement and regulation of cytoplasm The cytoplasm is the water-like substance but jelly in nature, and it contains so many things such as enzymes, salts, and other things. In the central area of the cytoplasm, it contains, single DNA structure in the form of nucleoid present, even the nuclear membrane is absent and complex structures like histones are absent in the prokaryotes,
So the correct option is D. DNA only present but not histones.
Note: Even in the time of reproduction, most of the time it happens asexually, even though genetic recombination happens but variations are very less compared to higher organisms, complex nuclear substances are absent in prokaryotes.