State the volume of air remaining in the lungs after a normal breathing.

1 Define vital capacity. What is its significance? 3 Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why? 4 What are the major transport mechanisms for CO2? Explain. 5 What will be the pO₂ and pCO₂ in the atmospheric air compared to those in the alveolar air ?  (i) pO₂ lesser, pCO₂ higher(ii) pO₂ higher, pCO₂ lesser(iii) pO₂ higher, pCO₂ higher(iv) pO₂ lesser, pCO₂ lesser