Final answer:
The notion that most of the O2 in the blood is dissolved in plasma is false; the majority is bound to hemoglobin in red blood cells.
Step-by-step explanation:
The statement that most of the O2 carried in the blood is dissolved in plasma is false. In the human body, oxygen transport is a crucial function of the blood, but only about 1.5 percent of oxygen is dissolved directly in the blood plasma. The vast majority, approximately 98.5 percent of the oxygen in the blood, is actually bound to a protein called hemoglobin which is found in red blood cells, or erythrocytes. This protein has a special component called heme, which contains iron, allowing it to bind up to four oxygen molecules, thereby enabling the transport of significant amounts of oxygen to tissues where it is needed for metabolic processes.