Which one of the following organisms belongs to the kingdom Monera?

Kingdom Monera consists of unicellular prokaryotic organisms that lack a defined nucleus and membrane-bound organelles [4]. This kingdom primarily includes bacteria and cyanobacteria (blue-green algae) [1]. Anabaena is a genus of filamentous cyanobacteria known for nitrogen fixation and is classified under Monera because of its prokaryotic cell structure [1]. In contrast, Diatoms and Euglena belong to the kingdom Protista; Diatoms are silica-encased eukaryotic algae [2], and Euglena is a flagellated eukaryotic protist [3]. Ulothrix is a multicellular green alga belonging to the kingdom Plantae (specifically the division Chlorophyta), characterized by eukaryotic cells with distinct chloroplasts [3]. Therefore, among the given options, only Anabaena fits the prokaryotic criteria of the Monera kingdom [1].

Sources

1. [4] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cyanidium
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 30: Climatic Regions > Geographical advantage > p. 466
3. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > 14.2 PHYTOPLANKTON > p. 207
4. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > 2.5 Why Is Cell Considered to Be a Basic Unit of Life? > p. 24