Question

Which of the following is a cyanobacteria?

• A. Spirogyra
• B. Glomus
• C. Oscillatoria
• D. Chlorella

Hint:

Recall that cyanobacteria are prokaryotic, unlike algae or fungi.

Answer 1

The Correct Option is C

Understanding the Concept:
Cyanobacteria (blue-green algae) are photosynthetic prokaryotes, so they have no nucleus or membrane-bound organelles, unlike true algae or fungi.

Check each option:
Spirogyra is a filamentous green alga, a eukaryote with a nucleus, so it is not a cyanobacterium.
Glomus is a fungus that forms mycorrhizal associations with plant roots.
Oscillatoria is a filamentous, gliding, prokaryotic blue-green alga that fixes nitrogen and carries out oxygenic photosynthesis, making it a true cyanobacterium.
Chlorella is a unicellular green alga, again a eukaryote.

Final Answer:
Only Oscillatoria is a prokaryotic photosynthetic organism, so it is the cyanobacterium among the four. \[ \boxed{\text{Oscillatoria}} \]