CAPF AC 2021 Q9: Science & Technology – Biology
Which one of the following organisms belongs to the kingdom Monera?
- (a) Diatom
- (b) Euglena
- (c) Anabaena
- (d) Ulothrix
Answer: (c) Anabaena
Explanation
Kingdom Monera
How to think: Monera means organisms with no true nucleus (prokaryotes).
That is bacteria and blue-green algae (cyanobacteria).
So look for the blue-green alga among the options.
Anabaena is one, along with Nostoc.
| Kingdom | Cell type | Examples |
|---|---|---|
| Monera | Prokaryotic, single-celled | Bacteria, Anabaena, Nostoc, Mycoplasma |
| Protista | Eukaryotic, single-celled | Diatoms, Euglena, Amoeba, Paramecium |
| Fungi | Eukaryotic, feed on dead matter | Yeast, mushroom |
| Plantae | Eukaryotic, make their own food | Ulothrix, Spirogyra, mosses, ferns |
| Animalia | Eukaryotic, eat other organisms | Insects, fish, humans |
The options placed:
| Organism | Kingdom |
|---|---|
| Diatom | Protista |
| Euglena | Protista |
| Anabaena | Monera |
| Ulothrix | Plantae (a green alga) |
Answer: (c) Anabaena.
Why each option is right or wrong
- (a) Incorrect. Diatoms are single-celled eukaryotes placed in Protista.
- (b) Incorrect. Euglena is a single-celled eukaryote placed in Protista.
- (c) CORRECT. Anabaena is a blue-green alga (cyanobacterium), a prokaryote of kingdom Monera.
- (d) Incorrect. Ulothrix is a green alga, a eukaryote placed in Plantae (Thallophyta).
Key point
Monera = prokaryotes: bacteria, blue-green algae (Anabaena, Nostoc), Mycoplasma. Diatoms and Euglena are Protista. Ulothrix and Spirogyra are green algae in Plantae.
Remember
Anabaena and Nostoc: blue-green algae, kingdom Monera.
Common mistakes
- Treating every alga as a plant; blue-green algae are bacteria in Monera.
- Placing Euglena in Monera because it is single-celled; it has a nucleus.
- Confusing Anabaena with Amoeba, which is a protist.
Exam tip
Educated guess: Anabaena and Nostoc are the two blue-green algae NCERT names, and both fix nitrogen. Blue-green alga means Monera.
Sources
- NCERT Class IX Science — Diversity in Living Organisms
- NCERT Class XI Biology — Biological Classification