Which of the following statements are true about respiration ?
(i) during inhalation, ribs move inward and diaphragm is raised
(ii) the gaseous exchange takes place in the alveoli
(iii) haemoglobin has greater affinity for carbon dioxide than oxygen
(iv) alveoli increase surface area for the exchange of gases

Options

A. (i) and (iv)
B. (ii) and (iii)
C. (i) and (iii)
D. (ii) and (iv)

Answer

D

Explanation

In human lungs, alveoli is balloonlike structure which provides a surface where the exchange of gases take place. The walls of alveoli consist of network of blood vessels. The air is sucked into the lungs to fill the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body.