Final answer:
Domain Archaea consists of single-celled prokaryotic organisms without a nucleus, distinct from Bacteria and Eukarya. They often inhabit extreme environments and are unique in their genetic and biochemical composition.
Step-by-step explanation:
Members of the Domain Archaea are characterized by simple cells that lack a nucleus and membrane-bound organelles, typically categorized as prokaryotes. Unlike the other domains, Eukarya, which includes complex organisms such as animals, plants, fungi, and protists, Archaea consists of unique single-celled organisms that often thrive in extreme environments such as hot springs.
They stand distinct from Bacteria, the other group of prokaryotes, due to differences in their genetic and biochemical makeup. Hence, the characteristics of members of the Domain Archaea align with option 'b. Simple cells, bacteria, protists.' However, it is essential to clarify that while Archaea are similar to Bacteria in being prokaryotes, they are a separate and distinct domain and should not be conflated with Bacteria or Protists.