Question

The figure given below shows a small part of the human lung where the exchange of gases takes place. In which one of the options given below, the one part A, B, C or D is correctly identified along with its function?

• A. B : Red blood cell - transport of CO2 mainly
• B. C : Arterial capillary - passes oxygen to tissues
• C. A : alveolar cavity - main site of exchange of respiratory gases
• D. D : Capillary wall - exchange of O2 and CO2 takes place here

Answer 1

The correct option is C A : alveolar cavity - main site of exchange of respiratory gases

Only A - alveolar cavity and B - red blood cell are correctly identified.
And among the two, red blood cell carries both CO2 as well as O2 and hence it is wrong.
Alveolar cavity is the site of exchange of respiratory gases. Hence it is the correct answer.