Name the most abundant and least number of leucocytes of blood.

Explanation

**Step-by-Step Solution:**

1. **Understanding Leucocytes:** Leucocytes, also known as white blood cells (WBCs), are crucial components of the immune system. They help defend the body against infections and foreign invaders.

2. **Types of Leucocytes:** There are several types of leucocytes, each with different functions. The main types include neutrophils, eosinophils, basophils, monocytes, and lymphocytes.

3. **Identifying the Most Abundant Leucocyte:** Among the various types of leucocytes, neutrophils are the most abundant. They typically make up about 60-70% of the total white blood cell count. Neutrophils are often referred to as the "soldiers" of the immune system due to their role in fighting off infections.

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