The nucleated blood cells whose number averages 6000-8000 `mm^(-3)` of blood have all of the following functions/characteristics, except

Options

A. Secretion of histamine
B. Phagocytosis
C. Diapedesis
D. Secretion of thromboplastin

Answer

To solve the question regarding the nucleated blood cells (leukocytes) and their functions, we will analyze the characteristics and functions of these cells step by step.

### Step 1: Identify the Type of Cells
The question mentions "nucleated blood cells" with a count of 6000-8000 per mm³ of blood. These cells are known as leukocytes or white blood cells (WBCs).

**Hint:** Remember that leukocytes are involved in the immune response and have various types with different functions.

### Step 2: Understand the Functions of Leukocytes
Leukocytes have several important functions, including:
- Providing immunity to the body.
- Phagocytosis (engulfing and digesting pathogens).
- Secretion of substances like histamine (involved in inflammatory responses).

**Hint:** Consider the different types of leukocytes and their specific roles in the immune system.

### Step 3: Analyze the Options
Now, we need to evaluate the options provided in the question regarding the functions of leukocytes:
1. **Secretion of histamine** - This is performed by basophils, a type of leukocyte.
2. **Phagocytosis** - This function is carried out by neutrophils and monocytes, both of which are leukocytes.
3. **Diapedesis** - This is the process by which leukocytes move out of the blood vessels to the site of infection or inflammation.
4. **Secretion of thromboplastin** - This function is not performed by leukocytes; it is the role of thrombocytes (platelets).

**Hint:** Focus on which function does not belong to leukocytes.

### Step 4: Identify the Incorrect Function
From the analysis, we see that the secretion of thromboplastin is not a function of leukocytes; it is a function of thrombocytes (platelets). Therefore, this option is the exception.

**Hint:** Look for the option that does not align with the known functions of leukocytes.

### Conclusion
The correct answer to the question is that leukocytes do not perform the function of "secretion of thromboplastin."

**Final Answer:** The nucleated blood cells (leukocytes) have all of the following functions/characteristics, except the secretion of thromboplastin.