(d) : Archaebacteria represent a cell type that seems to possess the characteristics of both prokaryotes as well as eukaryotes. In size, the archaebacteria are about 1μm in diameter, the size of typical prokaryotes lack membrane-bound organelles, nuclear bodies are not bound by nuclear membranes as it is in eukaryotes and ribosomes are 70 S, the size of those found in typical prokaryotes. They have unique cell wall that lacks peptidoglycan, closely resemble the eukaryotic cells in the mechanisms of protein synthesis, structural proteins, and RNA compliments of the ribosomes and a very distinctive feature of archaebacterial genes is the presence of introns, elements that are totally unknown in other prokaryotes, though relatively common in eukaryotes.Archaebacteria also possess unique characteristic found in neither eukaryotes nor prokaryotes. For example, their membrane contain branched chain lipids with ether. This enables them to tolerate extremes of heat and pH