This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
CO2 diffuses more easily through the respiratory membrane than O2 because it is 
Select and explain. 
A. Less dense, B. More soluble in plasma, C. Less molecular weight, D. Less PCO2 in the alveoli
B: More soluble in plasma
Answer: B: More soluble in plasma 
Explanation: Diffusion of Gases Through Liquids The more soluble a gas is, the faster it will diffuse. In this case carbon dioxide diffuses much faster than oxygen, as it is much more soluble. Ref: guyton and hall textbook of medical physiology 12 edition page number:348,349,350