Final answer:
Carbon dioxide dissolves better in plasma than oxygen mainly because it is more soluble in water, not because it binds more strongly to hemoglobin.
Step-by-step explanation:
The reason carbon dioxide dissolves better in plasma than oxygen is that carbon dioxide is more soluble in water. This greater solubility allows carbon dioxide to be transported in the blood in several ways. Approximately 5 to 7 percent of carbon dioxide is dissolved directly in the plasma. In addition, carbon dioxide can bind to plasma proteins or to hemoglobin within red blood cells, forming a molecule called carbaminohemoglobin.
It's important to note that while you may have seen statements suggesting that carbon dioxide has more affinity for hemoglobin than oxygen, in the context of this question, the correct answer is that the higher solubility of carbon dioxide in plasma is the predominant factor that explains why more carbon dioxide is dissolved in plasma compared to oxygen. Oxygen's transport is primarily facilitated by its binding to hemoglobin, rather than being dissolved in plasma.