Which of the following are involved in body defence ?

Options

A. (a) Neutrophils
B. (b) Lymphocytes
C. (c) Macrophages
D. (d) All of the above

Answer

To answer the question "Which of the following are involved in body defence?", we will analyze the options provided and determine their roles in the immune system.

### Step-by-Step Solution:

1. **Understanding Body Defence**:
- Body defence refers to the mechanisms that the body uses to protect itself from pathogens, which include microorganisms and viruses that can cause harm.

2. **Identifying the Immune System**:
- The immune system is the body's natural defence mechanism. It consists of various immune cells that work together to identify and eliminate pathogens.

3. **Analyzing the Options**:
- **Option A: Neutrophils**:
- Neutrophils are a type of white blood cell and are the most abundant immune cells in the body. Their primary function is phagocytosis, which involves engulfing and destroying pathogens.
- **Option B: Lymphocytes**:
- Lymphocytes are another type of immune cell that includes B cells and T cells. B cells are produced in the bone marrow and are responsible for producing antibodies, while T cells help in recognizing and remembering pathogens for future responses.
- **Option C: Macrophages**:
- Macrophages are large immune cells that also perform phagocytosis. They are crucial for engulfing pathogens and presenting antigens to other immune cells.
- **Option D: All of the above**:
- Since all the mentioned cells (neutrophils, lymphocytes, and macrophages) are involved in body defence, this option suggests that all of them contribute to the immune response.

4. **Conclusion**:
- Since neutrophils, lymphocytes, and macrophages all play essential roles in the immune system and body defence, the correct answer is **Option D: All of the above**.

### Final Answer:
**D: All of the above**

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