Read the statements below and identify the one that will not help in increasing the efficiency of gaseous exchange in the alveoli .

Options

A. The blood capillaries and alveoli have a large total surface area.
B. The blood flow is slowed as it passes through the pulmonary capillaries .
C. The thickness of the respiratory membrane is increased
D. The walls of the alveoli and capillaries are very thin

Answer

To solve the question, we need to analyze the given statements regarding the efficiency of gaseous exchange in the alveoli and identify which one does not contribute positively to this process.

### Step-by-Step Solution:

1. **Understanding Gaseous Exchange**: Gaseous exchange in the alveoli is crucial for oxygen uptake and carbon dioxide removal. The efficiency of this process is influenced by several factors, including surface area, thickness of membranes, and blood flow.

2. **Evaluating the Statements**:
- **Statement 1**: "The blood capillaries and alveoli have large total surface area."
- **Analysis**: A larger surface area facilitates more gas exchange. This statement supports efficient gaseous exchange.

- **Statement 2**: "The blood flow is slowed as it passes through the pulmonary capillaries."
- **Analysis**: Slowing down blood flow allows more time for gas exchange to occur. This statement also supports efficient gaseous exchange.

- **Statement 3**: "Thickness of the respiratory membrane is increased."
- **Analysis**: An increase in thickness of the respiratory membrane would hinder gas diffusion, making it less efficient. This statement does not support efficient gaseous exchange.

- **Statement 4**: "The walls of the alveoli and capillaries are very thin."
- **Analysis**: Thin walls facilitate easier diffusion of gases, thus supporting efficient gaseous exchange.

3. **Identifying the Correct Answer**:
- The only statement that does not help in increasing the efficiency of gaseous exchange is **"the thickness of the respiratory membrane is increased."** This is because increased thickness would impede the diffusion of gases.

### Conclusion:
The statement that will not help in increasing the efficiency of gaseous exchange in the alveoli is: **"The thickness of the respiratory membrane is increased."**

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