What is true about Haldane effect ?
(a) Occurs at the level of lungs
(b) Diffusion of `CO_(2)` in alveoli from blood
(c) Formation of oxyhaemoglobin

Options

A. a and c
B. a, b and c
C. b and c
D. None of these

Answer

To determine what is true about the Haldane effect, let's analyze each option step by step.

### Step 1: Understanding the Haldane Effect
The Haldane effect refers to the physiological phenomenon where deoxygenation of the blood increases its ability to carry carbon dioxide (CO2). This effect is particularly significant in the lungs, where oxygen is taken up and CO2 is released.

### Step 2: Evaluating Option (a) - Occurs at the level of lungs
The Haldane effect does indeed occur at the level of the lungs. In the lungs, as oxygen binds to hemoglobin, it promotes the release of CO2 from the blood. Therefore, this statement is **true**.

### Step 3: Evaluating Option (b) - Diffusion of CO2 in alveoli from blood
This statement describes the process where CO2 diffuses from the blood into the alveoli to be exhaled. The Haldane effect facilitates this process by enhancing the release of CO2 when hemoglobin is oxygenated. Therefore, this statement is also **true**.

### Step 4: Evaluating Option (c) - Formation of oxyhemoglobin
The formation of oxyhemoglobin occurs when oxygen binds to hemoglobin. While this process is related to the Haldane effect, the statement itself does not accurately describe the Haldane effect, which focuses on the increased capacity for CO2 transport when hemoglobin is deoxygenated. Thus, this statement is **not true** in the context of the Haldane effect.

### Conclusion
Based on the evaluation:
- (a) True
- (b) True
- (c) Not true

The correct options regarding the Haldane effect are (a) and (b).