Question

The viruses which attack blue-green algae are termed as
A. Bacteriophages
B. Cyanophages
C. Mosaic viruses
D. Phages

Answer 1

Hint: Phages are usually referred to as bacteriophage viruses. The virus which infects bacteria is called bacteriophage. Blue-green algae are also called cyanobacteria, but bacteriophages do not attack them.

Complete answer: Viruses are different from normal organisms in the sense that a virus always acts as a matter outside a living cell. Upon finding a living cell, a virus injects its genetic material into the cell and the genetic material gets integrated with the gnome of the host cell.
As the host cell replicates, the viral genome also multiplies it.
Viruses are usually infectious, but there is some good virus known as bacteriophages.
These infect bacteria which may otherwise cause harm to us.
The viruses which attack and infect blue-green algae are called cyanophages.

So, the correct option is B. Cyanophages

Note: Cyanobacteria have prokaryotic structure but they function like eukaryotes and are able to undergo photosynthesis. These also help in nitrogen fixation. Blue-green algae are also called Cyanophyta or cyanobacteria. As the target organism of the virus is cyanobacteria, hence it is named likewise. Mosaic viruses are the ones that infect plant cells (e.g. Tobacco Mosaic Virus).