Carbon dioxide dissolves more readily in the blood than oxygen does. Normal carbon dioxide levels within blood ranges between 5% and 7%, whereas 1.5% of oxygen in the blood is dissolved directly into the blood itself. What is the partial pressure, in mmHg, of carbon dioxide in arterial blood for a patient with 6.5% CO who has 120 mmHg systolic pressure? 7.8 mmHg 6.0 mmHg 8.4 mmHg 1.8 mmHg