Question

Blue-green algae belong to ____________
A) Plantae
B) Fungi
C) Monera
D) Protista

Answer 1

Hint: Blue-green algae are also known as cyanobacteria that belong to the kingdom containing organisms that are devoid of a true nucleus and other membrane-bound organelles. The members of this kingdom are unicellular and reproduce by binary fission.

Complete answer:
Option (A): Kingdom Plantae contains autotrophic eukaryotic organisms that are multicellular. The members of this kingdom contain a true nucleus and membrane-bound organelles. This kingdom includes various plants like mango, sunflower, pea, potato, etc.
 Option (B): Kingdom Fungi contains heterotrophic eukaryotic organisms that are multicellular. The cell wall of fungus is composed of glucan and chitin. This kingdom includes yeast, molds, etc.
Option (C): Kingdom Monera consists of unicellular organisms that are prokaryotic i.e., devoid of a true nucleus and membrane-bound organelles. This kingdom includes bacteria and archaea. Cyanobacteria or blue-green algae come under the kingdom Monera because of its prokaryotic cell organization.
Option (D): Kingdom Protista includes single-celled eukaryotic organisms i.e., Amoeba, Paramecium, etc. The members of this kingdom possess flagella or cilia that aid in locomotion.

Hence, the correct option is (C).

Additional Information: The blue-green algae or cyanobacteria are a group of photosynthetic bacteria and some of them are capable of fixing nitrogen in anaerobic conditions due to the presence of specialized cells called heterocysts that contain enzymes necessary for fixing nitrogen i.e., nitrogenase.

Note: Blue-green algae belongs to the kingdom Monera that are autotrophic and derive their energy from oxygenic photosynthesis. The blue-green algae or cyanobacteria produce toxins called cyanotoxins that can cause harm to animals and humans.