Final answer:
The arteries of the pulmonary circuit carry deoxygenated blood, which is then oxygenated in the lungs before returning to the heart. This contrasts with the systemic circuit, where arteries transport oxygenated blood to the body's tissues.
Step-by-step explanation:
In the cardiovascular system's circuits, deoxygenated blood is present in the arteries of the pulmonary circuit. Unlike the systemic circuit, where arteries carry blood rich in oxygen to the body's tissues, the pulmonary circuit works differently. In the pulmonary circuit, arteries carry deoxygenated blood from the right ventricle to the lungs. Here, the exchange of gases occurs; carbon dioxide is released, and oxygen is absorbed. The oxygenated blood then returns to the heart through the pulmonary veins, making option a. (Blood in the pulmonary vein is deoxygenated) a false statement. Conversely, systemic veins carry deoxygenated blood back to the heart, as seen with the inferior vena cava, which indeed has deoxygenated blood, making option b. correct. Option c. (Blood in the pulmonary artery is deoxygenated) is also correct, and option d. (Blood in the aorta is oxygenated) is true, as the aorta carries oxygenated blood from the left ventricle to the body.