The correct answer is (d) (ii) and (iv).
Explanation:
(ii) In the alveoli, exchange of gases takes place:
This is where the primary gas exchange occurs. Oxygen diffuses from the alveolar air into the bloodstream, and carbon dioxide diffuses from the blood into the alveolar air.
(iv) Alveoli increase surface area for exchange of gases:
The large number of tiny alveoli in the lungs significantly increases the surface area available for gas exchange to happen efficiently.
Why the other options are incorrect:
(i) During inhalation, ribs move inward and diaphragm is raised:
This statement is incorrect. During inhalation, the ribs move outward and the diaphragm contracts (downward), increasing the volume of the thoracic cavity.
(iii) Haemoglobin has greater affinity for carbon dioxide than oxygen:
This statement is incorrect. Haemoglobin has a greater affinity for oxygen than carbon dioxide. While carbon dioxide is initially transported in the blood bound to haemoglobin, it is primarily transported dissolved in the plasma.