Which of the following statements(s) is (are) true about respiration?
(a) During respiration, ribs move inward, the diaphragm is raised.
(b) In the alveoli, exchange of gases takes place, i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from the blood into the alveolar air.
(c) Haemoglobin has a greater affinity for oxygen than carbon dioxide.
(d) Alveoli increases the surface area for the exchange of gases.