`phixx-174` bacteriophage has

Options

A. Single strand DNA
B. Double strand RNA
C. Double strand DNA
D. Single strand RNA

Answer

To answer the question about the `phixx-174` bacteriophage, we need to analyze the information provided in the video transcript step by step.

### Step-by-Step Solution:

1. **Understanding Bacteriophages**:
- Bacteriophages, or phages, are viruses that infect bacteria. They consist of genetic material (DNA or RNA) surrounded by a protein coat.

**Hint**: Remember that bacteriophages specifically target bacterial cells.

2. **Identifying the Type of Genetic Material**:
- The transcript mentions that `phixx-174` has DNA. This is crucial because it differentiates it from other types of viruses that may have RNA.

**Hint**: Focus on the distinction between DNA and RNA viruses.

3. **Determining the Structure of the DNA**:
- The transcript states that the DNA of `phixx-174` is described as "positive sense circular single-stranded DNA." This means that the DNA is circular in shape and consists of a single strand, which is a unique characteristic of some bacteriophages.

**Hint**: Circular single-stranded DNA is less common than double-stranded DNA, so keep that in mind.

4. **Conclusion**:
- Based on the information provided, `phixx-174` bacteriophage has single-stranded DNA, specifically positive-sense circular single-stranded DNA.

**Hint**: Summarize the key characteristics: single-stranded, circular, and DNA.

### Final Answer:
The `phixx-174` bacteriophage has single-stranded DNA.