Final answer:
The most common circulatory approach in animals is the closed circulatory system, allowing efficient transport of blood, separate from interstitial fluid, which is a feature of vertebrates like mammals and birds, with the most advanced form being the four-chambered heart system.
Step-by-step explanation:
The most common approach to circulation in animals is the closed circulatory system. In a closed circulatory system, blood is contained within a network of vessels, separate from the body's interstitial fluid. This system provides efficient transport of nutrients, gases, and metabolic waste throughout the body. Vertebrates, including mammals, birds, reptiles, amphibians, and fish, utilize this system, which has evolved to effectively support higher metabolic demands and diverse life functions.
For example, fish have a simpler closed circulatory system with a two-chambered heart, allowing blood to flow unidirectionally. Mammals and birds exhibit the most complex system with a four-chambered heart ensuring no mixing of oxygenated and deoxygenated blood, which allows for high metabolic rates.