In the light of recent classification of living organisms into three domains of life (bacteria, archaea and eukarya), which one of the following statements is true about archaea ?
Archae have some novel features that are absent in other prokaryotes and eukaryotes.
The lipids that comprise their membranes are unique, resembling neither the Bacteria nor the Eukarya. Certain members of the Archaea are able to produce methane gas, another unique characteristic. It has been observed that many of the Archaea prefer to live in extremes of temperature, salt concentration, and pH—environmental conditions thought to be similar to those found on Earth over 3.5 billion years ago when life first originated.
The Archaea share certain characteristics with Bacteria, others with Eukarya, and have some characteristics that are unique.
For example, cells of the Archaea are structurally more similar to Bacteria, live predominantly as single cells, and have cell walls, although the walls do not contain the complex material called peptidoglycan that is of the Bacteria. Like the Bacteria, the Archaea lack a membrane-enclosed nucleus and their DNA exists in a circular form.
On the other hand, their DNA is associated with histones, a characteristic of Eukarya.