Pick out the statement that does not apply to viroids

Options

A. Infection agents smaller than viruses
B. Cause potato spindle tuber disease
C. Have free DNA
D. Lack protein coat

Answer

To solve the question "Pick out the statement that does not apply to viroids," we will analyze each statement provided and determine which one is incorrect regarding viroids.

### Step-by-Step Solution:

1. **Understand Viroids**: Viroids are infectious agents that are smaller than viruses. They are composed solely of a short strand of circular single-stranded RNA and do not have a protein coat.

2. **Analyze Each Statement**:
- **Statement 1**: "Infection agents smaller than viruses."
- This statement is true. Viroids are indeed smaller than viruses.

- **Statement 2**: "Cause potato spindle tuber disease."
- This statement is also true. The first identified viroid was responsible for potato spindle tuber disease.

- **Statement 3**: "Have free DNA."
- This statement is false. Viroids do not have DNA; they consist of RNA. Therefore, this statement does not apply to viroids.

- **Statement 4**: "Lack protein coat."
- This statement is true. Viroids do not have a protein coat, which distinguishes them from viruses.

3. **Conclusion**: The statement that does not apply to viroids is **Statement 3**, which claims that viroids have free DNA.

### Final Answer:
The statement that does not apply to viroids is **"Have free DNA."**

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