Which of the following organisms are classified as prokaryotes?

Prokaryotes are defined as single-celled organisms that lack a distinct nucleus and other membrane-bound organelles. The classification of organisms into prokaryotes and eukaryotes is fundamental in biology.

Bacteria and archaea fall into the prokaryotic category. Both groups share the characteristic of being unicellular and have simple cell structures compared to eukaryotes, which include organisms like plants, animals, and fungi. Bacteria are perhaps the most well-known prokaryotes, and they can be found in a diverse range of environments. Archaea, while also prokaryotic, are often found in extreme environments and have distinct molecular characteristics that differentiate them from bacteria.

In contrast, fungi, plants, animals, protozoa, and algae are all classified as eukaryotes because they have a nucleus and complex cell structures. This distinction helps to clarify the organization and complexity of different life forms on Earth, emphasizing why the classification of bacteria and archaea as prokaryotes is accurate.