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.

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: 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.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
 

In the light of the above statements choose the correct answer from the options given below:
 

Assertion: Rarely, emphysema may be caused by the deficiency of the enzyme Alpha 1 antitrypsin deficiency.
Reason: Deficiency of alpha-1 antitrypsin leads to a chronic uninhibited tissue breakdown.

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

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R): 

In the light of the above statements choose the correct answer from the options given below:

Assertion: The respiratory system of a bird more efficient than the human respiratory system.
Reason: The bird respiratory system does not mix exhaled air with inhaled air.

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

Most of the aquatic arthropods respire through:

What prevents the entry of food into the larynx during deglutition?
1. A thin elastic cartilaginous flap
2. A thick fibrous cartilaginous flap
3. A thick elastic cartilaginous flap
4. A thin calcified cartilaginous flap

The trachea divides into a right and a left primary bronchus at the level of: