National Academy of Sports Medicine (NASM) Group Fitness Instructor Practice Exam 2026 – All-in-One Guide to Achieve Certification Success!

Blood is the life-sustaining fluid that circulates throughout the body, delivering essential oxygen and nutrients to the organs and cells. It consists of various components, including red blood cells that carry oxygen, white blood cells that support the immune system, and platelets involved in clotting. Additionally, blood plasma serves as the liquid portion of blood, containing water, hormones, and waste products.

While plasma is crucial as a component of blood, it is not the complete fluid responsible for transporting oxygen and nutrients on its own. Lymph primarily plays a role in the immune system and in the transport of fats and fat-soluble vitamins, rather than serving as the main transport medium for oxygen and nutrients. Interstitial fluid surrounds cells and acts as a vehicle for substances exchanged between blood capillaries and cells, but it is the blood that performs this vital function for the entire body systemically. Therefore, blood is the correct answer as it embodies the comprehensive mechanism of transport for these life-sustaining elements throughout the human body.