Defining lysogeny — Which type of virus is specifically capable of establishing a long-term relationship with a host cell known as lysogeny?

Introduction / Context:
Lysogeny is a hallmark of temperate bacteriophages, in which the viral genome integrates into, or persists within, the host genome as a prophage without immediate lysis. Understanding this state is key for phage genetics and bacterial evolution.

Given Data / Assumptions:

• Lysogeny = stable, heritable association (prophage) with the host chromosome.
• Temperate phages can switch between lysogenic and lytic cycles.
• “Adsorbed virus” merely indicates attachment and does not define life-cycle strategy.

Concept / Approach:
Only temperate viruses are defined by their ability to form lysogens. While many temperate phages are DNA phages, “DNA phage” is not synonymous with temperate; some DNA phages are strictly lytic. Therefore, the precise term is “Temperate virus.”

Step-by-Step Solution:

Verification / Alternative check:
Lambda phage is the classic temperate phage model demonstrating integration and induction.

Why Other Options Are Wrong:

• Adsorbed virus: refers only to attachment.
• RNA phage: most known are lytic; lysogeny is uncommon in canonical RNA phages.
• DNA phage: too broad—includes both lytic and temperate phages.

Common Pitfalls:
Equating genome type (DNA vs RNA) with life-cycle strategy; temperateness is a behavioral category, not a genome-type category.

Final Answer:
Temperate virus