Respiration pathway — arrange airflow and oxygen transfer steps correctly: A) Lung B) Nostrils C) Windpipe D) Blood

Introduction / Context:
Trace the path of inhaled air to oxygen transfer into blood.

Given Data / Assumptions:
Nostrils → Windpipe (trachea) → Lung → Blood (via alveoli).

Concept / Approach:
Follow anatomical route of air and diffusion.

Step-by-Step Solution:
Nostrils (B) admit air.Windpipe (C) conducts air to lungs.Lung (A) houses alveoli.Blood (D) receives O2 across alveolar membranes.

Verification / Alternative check:
Basic physiology confirms this pathway.

Why Other Options Are Wrong:
They misorder anatomical structures or start with blood.

Common Pitfalls:
Confusing trachea with esophagus.

Final Answer:
B, C, A, D