Clotting of blood occurs due to the presence of _____ in blood.

Options

A. haemoglobin
B. white blood corpuscles
C. red blood corpuscles
D. platelets

Explanation

**Step-by-Step Solution:**

1. **Understanding Blood Components**: Blood is composed of various components, including red blood cells, white blood cells, platelets, and plasma. Each component has a specific function.

2. **Identifying the Role of Platelets**: Among these components, platelets (also known as thrombocytes) play a crucial role in the clotting process. They are small cell fragments that are essential for stopping bleeding.

3. **Mechanism of Clotting**: When a blood vessel is injured, platelets quickly gather at the site of the injury. They adhere to the exposed tissue and each other, forming a temporary "platelet plug."

4. **Release of Clotting Factors**: In addition to forming a plug, platelets release various substances that help in the coagulation cascade, leading to the formation of a stable blood clot.

5. **Conclusion**: Therefore, the presence of platelets in the blood is what facilitates the clotting process.

6. **Final Answer**: Clotting of blood occurs due to the presence of **platelets** in blood.

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