Which of the following conditions is found in the alveoli which is favourable for the formation of oxyhaemoglobin ?

Options

A. Higher `H^+` concentration
B. Low `pO_2`
C. Low temperature
D. High `pCO_2`

Answer

To solve the question regarding the conditions in the alveoli that are favorable for the formation of oxyhemoglobin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Oxyhemoglobin Formation**:
- Oxyhemoglobin (HbO2) is formed when hemoglobin (Hb) binds with oxygen (O2). This reaction primarily occurs in the alveoli of the lungs, where oxygen is abundant.

2. **Identifying Favorable Conditions**:
- For the formation of oxyhemoglobin, certain conditions need to be favorable:
- **High Partial Pressure of Oxygen (pO2)**: A high pO2 in the alveoli promotes the binding of oxygen to hemoglobin.
- **Low Partial Pressure of Carbon Dioxide (pCO2)**: A low pCO2 is necessary because high levels of carbon dioxide can lead to the release of oxygen from hemoglobin (Bohr effect).
- **Low Hydrogen Ion Concentration (H+)**: A low concentration of hydrogen ions (which corresponds to a higher pH) is favorable for oxyhemoglobin formation.
- **Low Temperature**: Lower temperatures favor the binding of oxygen to hemoglobin.

3. **Analyzing the Given Options**:
- **High H+ Concentration**: This is incorrect as it should be low for oxyhemoglobin formation.
- **Low pO2**: This is also incorrect because a high pO2 is required.
- **Low Temperature**: This is correct as lower temperatures favor oxyhemoglobin formation.
- **High pCO2**: This is incorrect since a low pCO2 is needed.

4. **Conclusion**:
- The only condition from the options provided that is favorable for the formation of oxyhemoglobin in the alveoli is **low temperature**.

### Final Answer:
- The correct answer is **low temperature**.