RNA particles causing symptoms like that of a viral disease are known as

Options

A. virion
B. phages
C. viroids
D. viruses

Answer

To answer the question "RNA particles causing symptoms like that of a viral disease are known as," we will analyze the options provided and identify the correct one step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question is asking for a specific type of RNA particle that causes symptoms similar to those caused by viral diseases.

2. **Analyzing the Options**:
- **Option A: Varion**: This term is not commonly used in the context of RNA particles. Variants of viruses may exist, but they are not specifically RNA particles causing symptoms.
- **Option B: Phages**: Phages, or bacteriophages, are viruses that specifically infect bacteria. They do not fit the description of RNA particles causing viral-like symptoms in other organisms.
- **Option C: Viroids**: Viroids are small, circular strands of RNA that lack a protein coat. They are known to cause diseases in plants and exhibit symptoms similar to those caused by viruses.
- **Option D: Viruses**: Viruses are infectious agents that contain either RNA or DNA and have a protein coat. While they can cause viral diseases, they do not fit the specific description of being solely RNA particles without a protein coat.

3. **Identifying the Correct Answer**: Based on the analysis, viroids (Option C) are the only entities that are RNA particles and cause symptoms similar to viral diseases without having a protein coat.

4. **Conclusion**: Therefore, the correct answer to the question is **Option C: Viroids**.