Final answer:
The capillary beds have the highest total cross-sectional area in the systemic vascular system, facilitating efficient exchange between blood and tissues.
Step-by-step explanation:
The vessels of the systemic vascular system with the highest total cross-sectional area are the capillary beds. Despite the small diameter of an individual capillary compared to that of an arteriole, the total number of capillaries is vastly greater, resulting in a larger total cross-sectional area. This is crucial because it allows for efficient exchange of nutrients, gases, and waste products between blood and tissues. Blood pressure decreases across the system with a significant drop at the arterioles due to their role as resistance vessels. Venous vessels, although larger in diameter, do not have a higher total cross-sectional area due to their smaller number compared to capillaries