The latest view about the origin of viruses is that viruses

Options

A. arise from nucleic acid and proteins in sea water
B. arise from bacteria by loss of cell wall
C. arise from archaebacteria
D. arise from plasmid/episome as free genes.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the latest view regarding the origin of viruses. We need to identify the source from which viruses are believed to have originated.

2. **Defining Key Concepts**:
- **Horizontal Gene Transfer**: This is the process by which genetic material is transferred between organisms in a manner other than traditional reproduction (parent to offspring). It is significant in increasing genetic diversity among organisms.
- **Genetic Diversity**: This refers to the total number of genetic characteristics in the genetic makeup of a species. It plays a crucial role in the adaptability and evolution of species.

3. **Exploring the Evolutionary History of Viruses**: The evolutionary history suggests that viruses may have originated from plasmids. Plasmids are small, circular, double-stranded DNA molecules that can replicate independently of chromosomal DNA.

4. **Mechanism of Virus Origin**: The current view posits that viruses arose when pieces of plasmid DNA moved between cells. This movement allowed for the evolution of viruses as entities that can infect hosts.

5. **Conclusion**: Based on the information gathered, the latest view is that viruses originated from plasmids (specifically, from plasmid epizomes), functioning as free genes.

6. **Final Answer**: Therefore, the correct answer is that viruses arise from plasmid epizomes as free genes.