NEET 2011 · Class 11

Breathing and Exchange of Gases

[DIAGRAM: A human lung alveolus surrounded by a capillary network showing exchange of oxygen and carbon dioxide across the alveolar-capillary membrane.] The figure given below shows a small part of human lung where exchange of gases takes place. Select the option which represents labelled part (A, B, C or D) correctly identified along with its function.

  1. (A)C: arterial capillary - passes oxygen to tissues
  2. (B)A : alveolar cavity - main site of exchange of respiratory gases
  3. (C)D : capillary wall - exchange of O2 and CO2 takes place here
  4. (D)B: red blood cells - transport of CO2 mainly

The NCERT line that answers it

Verbatim line

Alveoli are the primary sites of exchange of gases.

Chapter
Breathing and Exchange of Gases
Section
14.3 EXCHANGE OF GASES
Page
6
Words matched
9 of 9

The answer appears as a continuous sentence in NCERT. This is that sentence.

How this line gives the answer

0, emb=1.0, combined=1.0). Verified: high — The span 'Alveoli are the primary sites of exchange of gases' directly and conclusively states that the alveolar cavity (A) is the main site of gas exchange, which matches option B exactly.

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