Which of the following leucocytes destroy foreign organisms entering the body?
a. Eosinophils, b. Basophils, c. neutrophils, d. Monocytes, e. Lymphocytes

Options

A. Eosinophil
B. Basophil
C. Monocyte
D. Acidophil

Answer

To solve the question "Which of the following leucocytes destroy foreign organisms entering the body?" we need to analyze the functions of the different types of leucocytes (white blood cells) provided in the options.

### Step-by-step Solution:

1. **Identify the Types of Leucocytes:**
The options given are:
- a. Eosinophils
- b. Basophils
- c. Neutrophils
- d. Monocytes
- e. Lymphocytes

2. **Understand the Functions of Each Type:**
- **Eosinophils:** These are primarily involved in allergic reactions and do not play a direct role in destroying foreign organisms.
- **Basophils:** These cells are involved in inflammatory reactions and also do not directly destroy foreign organisms.
- **Neutrophils:** These cells are known for their role in phagocytosis, which is the process of engulfing and destroying foreign particles, including bacteria and pathogens.
- **Monocytes:** These cells also perform phagocytosis. They can engulf foreign particles and dead cells, acting as scavengers in the body.
- **Lymphocytes:** These cells are primarily involved in the immune response, producing antibodies and helping in the immune defense, but they do not directly destroy foreign organisms.

3. **Determine Which Cells Destroy Foreign Organisms:**
From the analysis:
- Neutrophils and Monocytes both have the ability to engulf and destroy foreign organisms through phagocytosis.
- Eosinophils, Basophils, and Lymphocytes do not directly destroy foreign organisms.

4. **Select the Best Answer:**
Since the question asks for the leucocytes that destroy foreign organisms, both Neutrophils and Monocytes are correct. However, if we have to choose one based on the common understanding of immediate response to foreign organisms, **Neutrophils** are often considered the first line of defense.

5. **Final Answer:**
The best answer to the question is **c. Neutrophils**. However, it is important to note that **d. Monocytes** also play a role in this process.