A characteristic feature of the closed circulatory system is the

Explanation

In a closed circulatory system, blood circulates within a network of vessels, allowing for efficient regulation of blood pressure. This system enables precise control over the distribution of nutrients and oxygen to various tissues. Unlike open systems, closed systems have capillaries that connect arteries and veins. Option B is correct as it highlights the regulation of blood pressure as a characteristic feature. Options A and C are incorrect because blood capillaries and respiratory pigments are present in closed systems. Option D describes an open circulatory system, where haemolymph flows in cavities, not a closed system.