Which of the following describes the primary functions of the circulatory system?

The primary functions of the circulatory system involve the transportation of nutrients, gases, and wastes throughout the body. This system, which includes the heart, blood vessels, and blood, plays a crucial role in maintaining homeostasis. It delivers essential substances such as oxygen from the lungs and nutrients from the digestive system to cells and tissues where they are needed. Additionally, the circulatory system takes away carbon dioxide and metabolic wastes, ensuring that the internal environment of the body remains stable and that tissues can function efficiently.

Transportation is the most fundamental aspect of the circulatory system; without it, cells would not receive the necessary nutrients and oxygen, nor would they be able to effectively eliminate wastes, leading to harmful buildup that can negatively impact health.

While the other options mention important functions related to the circulatory system, they do not encompass its primary role. Supporting the immune system is indeed a function of white blood cells and circulating antibodies but is secondary to transportation. Facilitating gas exchange happens specifically in the lungs and is part of the respiratory system, though the circulatory system transports the gases. Similarly, regulating temperature and pH contributes to homeostasis but is not the main purpose of the circulatory system itself, although these processes rely on the transportation functions.