What is leucocytosis ?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Term "Leucocytosis":**
- The term "leucocytosis" is derived from the Greek word "leuko," which means "white" or "colorless." It refers specifically to white blood cells (WBCs), also known as leukocytes.

2. **Types of Blood Cells:**
- In human blood, there are three main types of cells:
- Red Blood Cells (RBCs): Responsible for carrying oxygen.
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