Thermococcus, Methanococcus and Methanobacterium exemplify (a) bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria (b) bacteria that contain a cytoskeleton and ribosomes (c) archaebacteria that contain protein homologous to eukaryotic core histones (d) archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled.
Option C Thermococcus, Methanococcus and Methanobacterium are examples of archaebacteria which are characterized by a unique cell wall that lack peptidoglycan and consist of polysaccharides and protein and closely resemble the eukaryotic cell in the mechanism of protein synthesis, structural protein and RNA compliments of the ribosomes.
