Which statement is wrong ?

Options

A. Diffusion capacity of `CO_(2)` is 20–25 times higher than `O_(2)`
B. The partial pressure of CO2 is 5–6 mmHg less in systemic artery than in pulmonary vein
C. The partial pressure of O2 is almost same in hepatic portal vein and in pulmonary artery
D. Blood is the medium for the transport atom of `O_(2)` and `CO_(2)`

Answer

To determine which statement is wrong among the provided options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1**: "Diffusion capacity of carbon dioxide is 20-25% higher than oxygen."
- **Analysis**: This statement is true. Carbon dioxide (CO2) has a higher solubility in blood compared to oxygen (O2), which allows it to diffuse more readily. Therefore, this statement is correct.

2. **Statement 2**: "The partial pressure of CO2 is 5-6 mmHg less than the systemic arteries than in pulmonary vein."
- **Analysis**: This statement is also true. The partial pressure of carbon dioxide is indeed lower in systemic arteries compared to the pulmonary veins, as CO2 is released from the blood into the alveoli in the lungs. Thus, this statement is correct.

3. **Statement 3**: "Partial pressure of oxygen is almost the same in hepatic portal vein and in pulmonary artery."
- **Analysis**: This statement is false. The partial pressure of oxygen in the hepatic portal vein is typically lower than that in the pulmonary artery because oxygen is utilized by tissues, leading to a decrease in its partial pressure. Therefore, this statement is incorrect.

4. **Statement 4**: "Blood is the medium for the transport of oxygen and carbon dioxide."
- **Analysis**: This statement is true. Blood serves as the transport medium for both oxygen and carbon dioxide. Oxygen is carried by hemoglobin in red blood cells, while carbon dioxide is transported in various forms, including dissolved in plasma. Thus, this statement is correct.

### Conclusion:
The wrong statement among the four provided is **Statement 3**.

---