| Assertion (A): | In the walls of bronchi and bronchioles are present stretch receptors. |
| Reason (R): | Stretch receptors are stimulated by overstretching of the lungs. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| Assertion (A): | The tracheae, primary, secondary and tertiary bronchi and initial bronchioles are supported by incomplete cartilaginous rings. |
| Reason (R): | The cartilaginous rings prevent these structure from collapsing. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | The two lungs are covered by a double-layered pleura, with pleural fluid between them. |
| Reason (R): | Pleural fluid reduces the friction on the lung surface. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| Assertion (A): | The value of tidal volume in a healthy human is about 6000-8000 mL/min. |
| Reason (R): | The volume of air remaining in the lungs even after forcible expiration is 1100-1200 mL. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| Assertion (A): | \(O_2\) binds with Hb in an irreversible manner. |
| Reason (R): | \(CO_2\) combines with Hb both is an irreversible and reversible manner. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| Assertion (A): | The amount of CO2 that can diffuse through the diffusion membrane per unit difference in partial pressure is much higher compared to that of O2. |
| Reason (R): | The solubility of CO2 in blood is 20-25 times higher than that of O2. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |