Identify the correct statement regarding lymphatic system.

Options

A. Lymphatic vessels have valves to prevent backflow of blood
B. Left and right subclavian veins drain lymph into inferior vena cava
C. Right lymphatic duct collects lymph from most of the parts of gastrointestinal tract
D. Lymphatic vessels return lost plasma protein in blood stream

Answer

To identify the correct statement regarding the lymphatic system, we will evaluate each of the provided statements one by one.

### Step-by-Step Solution:

1. **Evaluate Statement A**:
- **Statement**: "Lymphatic vessels have walls to prevent backflow of blood."
- **Analysis**: This statement is incorrect because lymphatic vessels transport lymph, not blood. The primary function of lymphatic vessels is to return lymph to the bloodstream, and they do have valves to prevent backflow of lymph, not blood.
- **Conclusion**: This statement is **wrong**.

2. **Evaluate Statement B**:
- **Statement**: "Left and right subclavian veins drain lymph into the inferior vena cava."
- **Analysis**: This statement is also incorrect. The left and right subclavian veins collect lymph from the lymphatic system and drain it into the right atrium of the heart via the superior vena cava, not the inferior vena cava.
- **Conclusion**: This statement is **wrong**.

3. **Evaluate Statement C**:
- **Statement**: "Right lymphatic duct collects lymph from most parts of the gastrointestinal tract."
- **Analysis**: This statement is incorrect. The right lymphatic duct collects lymph from the right side of the body above the diaphragm. The gastrointestinal tract is primarily drained by the thoracic duct, which collects lymph from the rest of the body, including the lower parts.
- **Conclusion**: This statement is **wrong**.

4. **Evaluate Statement D**:
- **Statement**: "Lymphatic vessels return lost plasma protein in bloodstream."
- **Analysis**: This statement is correct. The lymphatic system plays a crucial role in returning lost plasma proteins, such as albumin, to the bloodstream. This process is essential for maintaining plasma osmotic pressure and fluid balance in the body.
- **Conclusion**: This statement is **correct**.

### Final Answer:
The correct statement regarding the lymphatic system is **"Lymphatic vessels return lost plasma protein in bloodstream."**

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