Viruses replicate in

Options

A. Dead tissue
B. In living cell
C. Culture medium
D. On living cell

Answer

To answer the question "Viruses replicate in:", we will analyze each option provided and determine where viruses can replicate.

### Step-by-Step Solution:

1. **Understanding Viruses**:
- Viruses are known as obligate intracellular parasites. This means they cannot replicate on their own and must enter a living cell to reproduce.

2. **Analyzing the Options**:
- **Option 1: Dead Tissue**:
- Dead tissue consists of dead cells that lack metabolic activity. Since viruses require a living host cell's machinery to replicate, they cannot replicate in dead tissue.
- **Conclusion**: Incorrect.

- **Option 2: Living Cells**:
- Living cells provide the necessary environment and machinery (like ribosomes, enzymes, etc.) for viruses to replicate. Viruses enter living cells and hijack their metabolic processes to produce new viral particles.
- **Conclusion**: Correct.

- **Option 3: Culture Medium**:
- Culture media are artificial environments used to grow cells in vitro. While they can support the growth of cells, viruses cannot replicate in culture media alone without living cells.
- **Conclusion**: Incorrect.

- **Option 4: On Living Cell**:
- This option is somewhat misleading. While viruses do attach to living cells, they do not replicate "on" the cell surface; they must enter the cell to utilize its machinery for replication.
- **Conclusion**: Incorrect.

3. **Final Answer**:
- Based on the analysis, the correct answer is **Option 2: Living Cells**.