Given below are two statements.

Statement I:  The exchange part of the respiratory system is where the actual diffusion of O₂ and CO₂ between blood and atmospheric air takes place.

Statement II: The part starting with the external nostrils up to the terminal bronchioles constitute the exchange part.

In light of the above statements, choose the correct answer from the options given below.

Statement I is correct but statement II is incorrect.

The exchange part of the respiratory system refers to the alveoli, where the actual exchange of oxygen (O₂) and carbon dioxide (CO₂) between the blood and atmospheric air occurs through diffusion.

The part of the respiratory system starting from the external nostrils up to the terminal bronchioles constitutes the conducting zone of the respiratory system. These structures conduct air to and from the exchange surfaces (alveoli) but do not participate in the actual exchange of gases.