Retroviruses in animals have the ability to transform normal cell into

Options

A. Tumour
B. RNA containing cell
C. DNA containing cell
D. Cancerous cell

Answer

**Step-by-Step Solution:**

1. **Understanding Retroviruses**: Retroviruses are a type of virus that have RNA as their genetic material. They can reverse transcribe their RNA into DNA once they infect a host cell.

2. **Mechanism of Action**: When retroviruses infect normal cells, they can integrate their genetic material into the host's DNA. This integration can disrupt normal cellular functions.

3. **Transformation of Cells**: The integration of viral DNA can lead to uncontrolled cell division and growth, which is a characteristic of cancerous cells. This means that retroviruses can transform normal cells into cancerous cells.

4. **Conclusion**: Based on the understanding of how retroviruses operate, we conclude that retroviruses in animals have the ability to transform normal cells into cancerous cells.

5. **Final Answer**: Therefore, the correct answer is that retroviruses in animals have the ability to transform normal cells into **cancerous cells**.

---