LIFE SCIENCE

Detailed explanation-1: -These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use.

Detailed explanation-2: -Bacteria and Archaea, the two prokaryotic kingdoms, grouped early in the evolution of life.

Detailed explanation-3: -Archaea is a group of prokaryotic life forms distinct from bacteria forming a separate domain of life. They possess pseudo-peptidoglycan cell wall, archaeol plus ether-linked plus highly branched isoprenoid chain lipids in their cell membrane with no nuclei or cell organelles.

Detailed explanation-4: -It has been challenged by the two-domain system that divides organisms into Bacteria and Archaea only, as Eukaryotes are considered as one group of Archaea.