Blood vessel carrying least `CO_(2)` is

Options

A. Pulmonary vein
B. Pulmonary artery
C. Vena Cava
D. Hepatic vein

Answer

To determine which blood vessel carries the least carbon dioxide (CO₂), we can analyze the function of each option provided:

1. **Understanding the Blood Vessels**:
- **Pulmonary Vein**: This vessel carries oxygenated blood from the lungs to the left atrium of the heart. Since this blood has just been oxygenated in the lungs, it contains the least amount of CO₂.
- **Pulmonary Artery**: This vessel carries deoxygenated blood from the right ventricle of the heart to the lungs. This blood has a higher concentration of CO₂ as it is being transported to the lungs for gas exchange.
- **Vena Cava**: This is a large vein that carries deoxygenated blood from the body back to the right atrium of the heart. This blood also has a significant amount of CO₂ since it has returned from the systemic circulation.
- **Hepatic Vein**: This vein carries deoxygenated blood from the liver back to the heart. It also contains CO₂, as it is returning from the liver, which processes nutrients and waste.

2. **Conclusion**:
- Among the options, the **pulmonary vein** carries the least CO₂ because it transports oxygen-rich blood from the lungs to the heart. Therefore, the correct answer is **option A: pulmonary vein**.

### Final Answer:
The blood vessel carrying the least CO₂ is the **pulmonary vein**.