[" 27.Thermococcus,Mtehanococcus and "],[" Methanobacterium exemplify :- "],[[" (1) Bacteria whose DNA is relaxed or positively "],[" supercoiled but which have a cytoskeleton as "],[" well as mitochondria "],[" (2) Bacteria that contain a cytoskeleton and "],[" (2) Archaebacteria that contain protein homologous "],[" (3) Archaebacteria that lack any histones resembling "],[" those found in eukaryotes but whose DNA is "],[" negatively supercoiled."]]