Assertion: Infant respiratory distress syndrome[hyaline membrane disease] is the leading cause of death of preterm infants.
Reason: The lungs of infants with respiratory distress syndrome are developmentally deficient in a material called surfactant.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion: Nitric oxide transport by hemoglobin to peripheral tissues is hypothesized to assist oxygen transport in tissues.
Reason: Nitric oxide can also be transported by hemoglobin bound to specific thiol groups in the globin protein.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the removal of carbon dioxide.
Reason: Oxygenated hemoglobin is a better proton donor than deoxygenated hemoglobin.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Chloride concentration is higher in systemic venous blood than in systemic arterial blood.
Reason: The rise in intracellular bicarbonate in RBCs leads to bicarbonate intake and chloride export.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: The medulla oblongata uses CSF pH as an indicator of blood carbon dioxide concentration.
Reason: Carbon dioxide is the main determinant of the pH of the CSF:

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Involuntary hyperventilation during an anxiety attack can cause the person to become faint because of:
1. increased ${\mathrm{CO}}_2$ levels caused by increase in cellular respiration, reducing brain perfusion and causing ischemia
2. decreased ${\mathrm{O}}_2$ levels in the blood, causing cells to lack enough ATP
3. effects of increased ${\mathrm{O}}_2$ levels in the blood and consequent constriction of cerebral blood vessels
4. lowered ${\mathrm{CO}}_2$ levels in the blood and consequent constriction of cerebral blood vessels

Assertion: Residual volume cannot be measured directly by spirometery.
Reason: The tidal volume, vital capacity, inspiratory capacity and expiratory reserve volume can be measured directly with a spirometer and are the basic elements of a ventilatory pulmonary function test.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: A person who is born and lives at sea level will develop a slightly smaller lung capacity than a person who spends their life at a high altitude.
Reason: The partial pressure of oxygen is lower at higher altitude which, as a result means that oxygen less readily diffuses into the bloodstream.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

In the given diagram, the functional residual capacity will be depicted by:

  
1.  B + F
2.  B + D + F
3.  A - [B + C]
4.  A - E

When a man inhales air containing normal concentration of O₂ as well as CO he suffers from suffocation because
1. CO reacts with ${\mathrm{O}}_2$, reducing its percentage in air
2. haemoglobin combines with CO instead of ${\mathrm{O}}_2$ and forms carboxyhaemoglobin
3. CO affects diaphragm and intercostal muscles
4. CO affects the nerves of the lungs