Diffusion of gas in the respiratory membrane: (A) Directly proportional to thickness of respiratory membrane, (B) Inversely proportional to molecular weight of the gas, (C) No lipid - water solubility, (D) Inversely proportional to pressure gradient
Answer is B. The rate of diffusion of gas across the respiratory membrane is
-        Directly proportional to 

The pressure gradient across the membrane
Lipid solubility of the gas 
The surface area of the membrane

-        Inversely proportional to

The thickness of the membrane​
The molecular weight of the gas