Carbon dioxide is transported by plasma and red blood cells. This is due to their high water solubility.
(1) Through plasma: 7% of is transported in a dissolved state by the plasma. Carbonic acid is formed when carbon dioxide reacts with water.

Because the formation of carbonic acid is a slow process, only a limited amount of carbon dioxide is transported this way.
(2) Through RBCs (Red Blood Cells): The red blood cells transport about 25 percent of as carbaminohaemoglobin. Carbaminohaemoglobin is formed when carbon dioxide attaches to the amino groups on the polypeptide chains of hemoglobin.

(3) Sodium bicarbonate transport: Sodium bicarbonate transports about 70% of carbon dioxide. In the presence of the enzyme carbonic anhydrase, diffuses into the blood plasma and mixes with water to create carbonic acid. Carbonic anhydrase is a zinc enzyme that accelerates carbonic acid production. Bicarbonate and hydrogen ions (H+) are formed when carbonic acid dissociates.