Which of the following events happen when air enters lungs
1. Ribs and sternum raised
2. volume of thorax increased
3. Diaphragm contracted
4. All of the above

Which of the following events happen when air expelled from lungs
1. Ribs and sternum returned to original position
2. volume of thorax decreased
3. Diaphragm relaxed and arched upwards
4. All of the above

Diffusion membrane consists of

1. Squamous epithelium of alveoli

2. endothelium of alveolar capillaries

3. Basement substance between them

4. All of the above

The diffusion membrane or respiratory membrane does not include

1. Thin squamous epithelium

2. Pseudostratified ciliated epithelium

3. Endothelium

4. Basement membrane 

Given below are the partial pressures (in mmHg) of oxygen and carbondioxide at different parts involved in diffusion in comparison to those in atmosphere.

Choose the correct option with respect to the values of partial pressures (in mmHg) marked as A, B, C and D

In alveoli,

1. pCO₂ is high and pO₂is low

2. pCO₂ is low and pO₂ is high

3. pCO₂ is low and pO₂ low

4. None of the above

More binding of CO₂ occurs when pCO₂ is _____ and pO₂ is ____

1. high, high

2. low, high

3. high, low

4. low, low

pCO₂ is high and pO₂ is low can be found in

1. alveoli

2. tissues

3. blood

4. heart

Transport of gases in alveoli takes place by:

The amount of CO₂ that can diffuse through the diffusion membrane per unit difference in partial pressure is much higher as compared to that of O₂. This is because: