Biology Respiration / Gaseous Exchange ETEA 2022
PMDC Verified Question 15 of 34
Which of the following part of human respiratory system forms the gas exchange surface?
A
Alveoli
B
Larynx
C
Bronchi
D
Trachea
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Alveoli
Concept: The respiratory system is divided into a conducting zone (bringing air in) and a respiratory zone (where actual gas exchange happens).

Solution:
  • The alveoli are clustered, highly vascularized microscopic sacs that form the terminal ends of the respiratory tree.
  • Their exceedingly thin squamous epithelium allows for the rapid diffusion of oxygen into the blood and carbon dioxide out of the blood.


Why other options are incorrect:
  • Trachea, Larynx, Bronchi: These are thick-walled, cartilaginous tubes belonging to the conducting zone. Gas cannot diffuse through their thick structural layers.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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