Final answer:
Prokaryotic cells, like bacteria and archaea, contain single, circular DNA molecules not wrapped around histone proteins, which are located in the nucleoid region.
Step-by-step explanation:
The genetic material of which kind of cells is included in a single, circular molecule of DNA devoid of any histone proteins? The answer lies within the characteristics of prokaryotic cells, specifically bacteria and archaea. Unlike eukaryotic cells, which contain linear DNA molecules tightly wrapped around histone proteins to form chromatin, prokaryotic cells house their genetic material in a single, circular DNA sequence that is not associated with histones. This circular DNA is located in a region of the cytoplasm known as the nucleoid. Prokaryotic organisms also sometimes carry plasmids, which are smaller loops of DNA that can encode additional genes, such as those providing antibiotic resistance.