The cells which directly attack and destroy the infected cells

Options

A. helper T-cells
B. natural killer cells
C. helper B-cells
D. killer T-cells

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for the type of cells that directly attack and destroy infected cells.

2. **Review the Options**: The options provided are:
- Natural Killer Cells
- Helper T Cells
- Helper B Cells
- Killer T Cells

3. **Analyze Each Option**:
- **Helper T Cells**: These cells primarily stimulate B lymphocytes to produce antibodies. They do not directly attack infected cells.
- **Natural Killer Cells**: These cells provide innate immunity and act as a barrier against infections, but they do not specifically target infected cells in the same way as Killer T Cells.
- **Helper B Cells**: These cells are responsible for synthesizing and transporting antibodies. They do not attack infected cells directly.
- **Killer T Cells**: Also known as cytotoxic T lymphocytes, these cells directly attack and destroy infected cells, including those infected by viruses and bacteria.

4. **Conclusion**: The cells that directly attack and destroy infected cells are the **Killer T Cells**.

**Final Answer**: Killer T Cells

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