Explanation:
- The virus which infects the bacteria is called bacteriophage.
- Bacteriophage was discovered by Twort & Filix
- It was named bacteriophage by D. Herelle.
- A bacteriophage is generally a double-stranded DNA virus
- In QB - bacteriophage - ss RNA is present.
- In ϕ X 174 - bacteriophage - ss DNA is present.
- A bacteriophage is of two types- Non-infective phages and infective phage.

Additional Information
- The animal virus was discovered by Loeffler & Frosch.
