By which physical process, thrombin is related?

Options

A. Excretion
B. Blood Clotting
C. Reproduction
D. Growth

Explanation

**Step-by-Step Solution:**

1. **Understanding Thrombin**: Thrombin is a naturally occurring enzyme in the body. It plays a crucial role in the process of blood coagulation.

2. **Function of Thrombin**: The primary function of thrombin is to convert fibrinogen, a soluble plasma protein, into fibrin, which is an insoluble protein that forms the meshwork of a blood clot.

3. **Relation to Physical Processes**: Among the options provided (excretion, blood clotting, reproduction, and growth), we need to identify which physical process thrombin is related to.

4. **Identifying the Correct Option**: Since thrombin is involved in the conversion of fibrinogen to fibrin, it is directly related to the process of blood clotting. This is a critical step in the body's response to bleeding and is essential for wound healing.

5. **Conclusion**: Therefore, the correct answer to the question is that thrombin is related to the physical process of blood clotting.

**Final Answer**: Blood clotting.

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