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 determine which condition in the alveoli is favorable for the formation of oxyhemoglobin, we need to analyze the provided options based on the physiological principles governing hemoglobin's behavior.

### Step-by-step Solution:

1. **Understanding Oxyhemoglobin Formation**:
- Oxyhemoglobin is formed when oxygen binds to hemoglobin in red blood cells. The binding is influenced by various factors, including the partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), hydrogen ion concentration (H+), and temperature.

2. **Analyzing the Options**:
- **Option a: Higher H+ concentration**:
- A higher concentration of H+ ions (lower pH) leads to the Bohr effect, which promotes the release (dissociation) of oxygen from hemoglobin. This is not favorable for oxyhemoglobin formation.

- **Option b: Low pO2**:
- Low partial pressure of oxygen (pO2) means that there is less oxygen available to bind with hemoglobin, which also promotes dissociation rather than formation of oxyhemoglobin.

- **Option c: Low temperature**:
- Lower temperatures favor the formation of oxyhemoglobin because they reduce the kinetic energy of molecules, leading to a more stable binding of oxygen to hemoglobin.

- **Option d: High pCO2**:
- High levels of carbon dioxide (pCO2) promote the release of oxygen from hemoglobin, thus favoring dissociation rather than formation of oxyhemoglobin.

3. **Conclusion**:
- Among the options analyzed, **low temperature (Option c)** is the condition that is favorable for the formation of oxyhemoglobin in the alveoli.

### Final Answer:
**c. Low temperature**