Which of the following is correct about the genome of viroid?

Options

A. It comprises of RNA having high molecular weight.
B. It comprises of either DNA or RNA.
C. It comprises of RNA associated with proteins.
D. It comprises of RNA having low molecular weight.

Answer

To solve the question about the genome of viroids, we will analyze the characteristics of viroids and evaluate the provided options.

### Step-by-Step Solution:

1. **Understanding Viroids**:
- Viroids are infectious agents that consist solely of a short strand of circular RNA. They do not have a protein coat, which differentiates them from viruses.

2. **Characteristics of Viroid RNA**:
- The RNA in viroids is known to have a low molecular weight. This is a key characteristic that we need to remember.

3. **Evaluating the Options**:
- **Option 1**: States that viroids have RNA of high molecular weight. This is incorrect because viroid RNA is of low molecular weight.
- **Option 2**: Claims that viroids comprise either DNA or RNA. This is also incorrect as viroids only contain RNA, not DNA.
- **Option 3**: Suggests that viroids comprise RNA associated with proteins. This is false because viroids lack any protein coat; they consist solely of RNA.
- **Option 4**: States that viroids comprise RNA having low molecular weight. This is correct as it aligns with our understanding of viroids.

4. **Conclusion**:
- After evaluating all the options, we can conclude that the correct statement about the genome of viroids is that they comprise RNA having low molecular weight (Option 4).

### Final Answer:
- The correct option is **Option 4**: "It comprises of RNA having low molecular weight."

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