A person remaining at high altitudes for years
becomes more and more acclimatized to the low
`pO_(2)` by the following except

Options

A. Increased pulmonary ventilation
B. Increased in RBCs and haemoglobin
concentration
C. Polycythemia
D. Increased cardiac output permanently

Answer

To solve the question regarding acclimatization of a person remaining at high altitudes for years, we need to analyze the physiological changes that occur in the body due to low partial pressure of oxygen (pO2).

### Step-by-Step Solution:

1. **Understanding Acclimatization**:
- Acclimatization refers to the physiological adjustments that occur in the body to cope with environmental changes, such as low oxygen levels at high altitudes.

2. **Physiological Changes at High Altitudes**:
- When a person lives at high altitudes (above 3500 meters), their body undergoes several changes to adapt to lower pO2. These changes include:
- **Increased Pulmonary Ventilation**: The respiratory rate increases to enhance oxygen intake.
- **Increased Red Blood Cell (RBC) Count**: The body produces more RBCs to carry more oxygen.
- **Increased Hemoglobin Concentration**: Higher hemoglobin levels in the blood improve oxygen transport.
- **Decreased Binding Affinity of Hemoglobin**: This allows for easier release of oxygen to tissues.

3. **Analyzing the Options**:
- The question asks for the option that does NOT contribute to acclimatization. The options typically include:
- Increased pulmonary ventilation (correct)
- Increased RBC count (correct)
- Increased hemoglobin concentration (correct)
- Increased cardiac output permanently (incorrect)

4. **Identifying the Incorrect Option**:
- Among the options, "increased cardiac output permanently" is the one that does not occur as a permanent adaptation. While cardiac output may increase temporarily to meet oxygen demands, it does not remain elevated permanently in acclimatized individuals.

5. **Conclusion**:
- Therefore, the correct answer to the question is that a person does not become acclimatized to low pO2 by "increased cardiac output permanently."

### Final Answer:
The correct option is: **Increased cardiac output permanently**.

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