Tick mark of incorrect statement .

Options

A. Every 100 ml of deoxygenated blood delivers approximately 4 ml of `CO_(2)` to the alveoli
B. Carbonic anhydrase is present in very high concentration in RBC
C. High `pCO_(2)` and low `pO_(2)` in tissues help in binding of carbon dioxide
D. `CO_(2)` is carried in haemoglobin as carboxyhaemoglobin

Answer

To solve the question of identifying the incorrect statement, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- The first statement claims that every 100 ml of deoxygenated blood delivers approximately 4 ml of carbon dioxide to the alveoli.
- This statement is correct as it aligns with physiological data regarding the transport of carbon dioxide in the blood.

2. **Evaluate the Second Statement:**
- The second statement states that carbonic anhydrase is present in very high concentration in red blood cells (RBCs).
- This statement is also correct because carbonic anhydrase is indeed an enzyme found in high concentrations in RBCs, facilitating the conversion of CO2 to bicarbonate.

3. **Evaluate the Third Statement:**
- The third statement mentions that high PCO2 and low PO2 in tissues help in the binding of CO2.
- This statement is accurate; high levels of carbon dioxide (PCO2) and low levels of oxygen (PO2) in tissues promote the binding of CO2 to hemoglobin.

4. **Evaluate the Fourth Statement:**
- The fourth statement claims that CO2 is carried in hemoglobin as carboxyhemoglobin.
- This statement is incorrect. CO2 is actually carried as carbaminohemoglobin, not carboxyhemoglobin. Carboxyhemoglobin refers to the binding of carbon monoxide (CO) to hemoglobin.

### Conclusion:
The incorrect statement is the fourth one: "CO2 is carried in hemoglobin as carboxyhemoglobin."

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