What is the function of plasma in blood?

Plasma serves a vital role in the circulatory system as it acts as the liquid component of blood, making up about 55% of its volume. Its primary function is to transport a variety of substances throughout the body. This includes nutrients absorbed from the digestive tract, hormones secreted by various glands, and waste products generated by metabolic processes that need to be removed from the tissues.

By serving as a medium for these substances, plasma facilitates the delivery of essential elements required for cellular function and the removal of metabolic byproducts, thereby maintaining a stable internal environment for the body (homeostasis). The continuous flow of plasma also helps regulate electrolyte balances and transport antibodies and proteins integral to the body's immune response.

While other options touch on important aspects of blood functions, they do not encapsulate the primary role of plasma as effectively. The transport of oxygen is primarily the role of red blood cells, and structural support is provided primarily by the blood cells themselves. Regulation of body temperature is achieved through various mechanisms, including blood flow and heat distribution, but this is not the primary function of plasma.