What is the primary function of blood in the human body?

The primary function of blood in the human body centers on its role in transporting oxygen and nutrients. Blood serves as a critical transportation medium, carrying oxygen from the lungs to the body's tissues and delivering essential nutrients absorbed from food to cells throughout the body. This process is vital for cellular metabolism, energy production, and overall bodily functions.

While filtering waste products is an important function of the kidneys—where blood is filtered to remove metabolic waste—it is not the primary function of blood itself.

Regulating body temperature is another important role, but it is more of a supportive function facilitated by blood flow and heat distribution rather than a primary purpose.

Producing hormones is a function carried out primarily by the endocrine glands, with hormones then being transported in the blood, but blood itself does not produce hormones. Ultimately, the primary role of blood is to ensure that oxygen and nutrients reach every part of the body, supporting life and health.