| I: | Prevents Lung Collapse | 
| II: | Facilitates Gas Exchange | 
Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because?
| 1. | there is a negative pressure in the lungs | 
| 2. | there is a negative intrapleural pressure pulling at the lung walls | 
| 3. | there is a positive intrapleural pressure | 
| 4. | pressure in the lungs is higher than the atmospheric pressure | 
| Assertion (A): | The thoracic chamber, being airtight, is critical for breathing. | 
| Reason (R): | Movement of rib cage can bring about inhalation and exhalation. | 
| 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. | (A) is False but (R) is True. | 
| Assertion (A): | Conducting part transports the atmospheric air to alveoli, clears it from foreign particles, humidifies it and also brings the air to body temperature. | 
| Reason (R): | The part of the respiratory system starting with the external nostrils upto terminal bronchioles constitutes the conducting part, whereas the alveoli from respiratory part. | 
| 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. | 
| Statement I: | The alveoli have ciliated cells in them to help expel dust particles that make it this far down into the respiratory tract. | 
| Statement II: | Gas exchange between the lungs and the blood, and between the blood and tissue fluid, is an active transport process. | 
| I: | Contraction of diaphragm | 
| II: | Contraction of internal intercostal muscles | 
| III: | Contraction of external intercostal muscles | 
| Statement I: | The respiratory membrane has one layer - the simple squamous epithelium of the alveoli. | 
| Statement II: | Oxygen diffuses faster from carbon dioxide across the respiratory membrane. |