Class 11 NEET Biology Breathing and Exchange of Gases

(a) : Blood is the medium of transport for O2 and CO2. About 97 percent of O2 is transported by RBCs in the blood. The remaining 3 percent of O2 is carried in a dissolved state through the plasma. Nearly 20−25 percent of CO2 is transported by RBCs whereas 70 percent of it is carried as bicarbonate. About 7 percent of CO2 is carried in a dissolved state through plasma.