Choose the incorrect statement.

Options

A. The role of oxygen in the regulation of respiratory rhythm is quite significant.
B. Receptors associated with aortic arch can recognize changes in `CO_2` & `H^+` concentration.
C. Decrease in concentration of `O_2` cannot activate chemosensitive area.
D. Chemosensitive area is located nearer to respiratory rhythm centre.

Answer

To solve the question of identifying the incorrect statement regarding the role of oxygen and other factors in the regulation of respiratory rhythms, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- The statement claims that "the role of oxygen (O2) in the regulation of respiratory rhythms is quite significant."
- **Evaluation:** This statement is incorrect because, while oxygen does play a role in respiration, its role in regulating respiratory rhythms is not significant compared to carbon dioxide (CO2) levels. The primary regulators of respiratory rhythm are CO2 and H+ ion concentrations.
- **Conclusion:** This is the incorrect statement.

2. **Analyze the Second Statement:**
- The statement mentions that "the receptors associated with the aortic arch recognize changes in CO2 and H+ concentration."
- **Evaluation:** This statement is correct. The chemoreceptors in the aortic arch are sensitive to changes in CO2 and H+ levels, which significantly influence respiratory rate and depth.
- **Conclusion:** This is a correct statement.

3. **Analyze the Third Statement:**
- The statement states that "a decrease in the concentration of oxygen (O2) cannot activate the chemosensitive area."
- **Evaluation:** This statement is also correct. The chemosensitive area is primarily activated by changes in CO2 levels rather than O2 levels. A decrease in O2 does not directly activate this area.
- **Conclusion:** This is a correct statement.

4. **Analyze the Fourth Statement:**
- The statement claims that "the chemosensitive area is located nearer to the respiratory rhythm center."
- **Evaluation:** This statement is correct. The chemosensitive area is indeed located adjacent to the respiratory rhythm center in the brain, allowing for efficient regulation of breathing.
- **Conclusion:** This is a correct statement.

### Final Conclusion:
- After evaluating all statements, the incorrect statement is the **first statement**: "the role of oxygen in the regulation of respiratory rhythms is quite significant."

### Summary:
- The incorrect statement is: **The role of oxygen (O2) in the regulation of respiratory rhythms is quite significant.**