Which of the following is a function of blood?

Blood plays a crucial role in the circulation of nutrients and waste throughout the body. It serves as a delivery system that transports oxygen, hormones, and various nutrients to cells while simultaneously carrying waste products, such as carbon dioxide and metabolic byproducts, away from the cells to be excreted. This dual function is essential for maintaining homeostasis and supporting cellular processes.

The other options do not accurately describe primary functions of blood. While blood may have peripheral roles in insulation and can contribute indirectly to energy storage, those functions are not central to its purpose. Respiration, on the other hand, notably involves the lungs and other respiratory structures. Thus, the circulation of nutrients and waste is the most accurate representation of a key function of blood in the body.