The coagulation of blood occurs due to

Options

A. Destruction of erythrocytes
B. Destruction of leucocytes
C. Change of fibrinogen into fibrin
D. Formation of serum

Answer

**Step-by-Step Solution:**

1. **Understanding Blood Coagulation**: Blood coagulation is a complex process that prevents excessive bleeding when there is an injury. It involves a series of biochemical reactions that lead to the formation of a blood clot.

2. **Identifying Key Components**: The main components involved in blood coagulation include platelets, clotting factors, fibrinogen, and thrombin.

3. **Role of Thrombin**: Thrombin is a crucial enzyme in the coagulation process. It acts as an activator that converts fibrinogen, a soluble plasma protein, into fibrin, which is an insoluble protein that forms the mesh of the blood clot.

4. **Conversion of Fibrinogen to Fibrin**: The specific step that leads to blood coagulation is the conversion of fibrinogen to fibrin. This process is initiated by thrombin, which is activated from prothrombin by a prothrombin activator.

5. **Formation of the Blood Clot**: Once fibrin is formed, it interacts with platelets to create a stable blood clot, effectively sealing the wound and preventing further blood loss.

6. **Evaluating the Options**:
- Option A (destruction of erythrocytes) is incorrect as it does not relate to the coagulation process.
- Option B (destruction of leukocytes) is also incorrect for the same reason.
- Option C (change of fibrinogen to fibrin) is correct as it directly describes the coagulation process.
- Option D (formation of serum) is not the primary mechanism of coagulation.

7. **Conclusion**: Therefore, the correct answer to the question "The coagulation of blood occurs due to" is option C: the change of fibrinogen to fibrin.

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