What is the primary function of blood within the cardiovascular system?

What is the primary function of blood within the cardiovascular system?

• A. Produces hormones
• B. Filters waste from the body
• C. Supplies oxygen and nutrients
• D. Regulates body temperature only

Answer: (C)

Blood's job in the circulatory system is to act as the transport system for the body. It carries what cells need to function to every part of the body. Oxygen from the lungs and nutrients from the digestive system are carried by the blood to all cells. Red blood cells use haemoglobin to pick up and deliver oxygen where it’s needed for energy production, while nutrients travel in the plasma to fuel metabolism. The blood also transports waste products to be removed by the lungs or kidneys, but the central idea is the delivery of oxygen and nutrients to sustain cellular activity. Other options point to things blood helps with, but they aren’t its main purpose. Producing hormones happens in glands, not in the blood itself, though hormones travel in the blood. Filtering waste is done by organs like the kidneys; blood carries waste but doesn’t filter it. Regulating temperature involves blood flow, but that’s a secondary effect of circulation, not the primary function.

Blood's job in the circulatory system is to act as the transport system for the body. It carries what cells need to function to every part of the body. Oxygen from the lungs and nutrients from the digestive system are carried by the blood to all cells. Red blood cells use haemoglobin to pick up and deliver oxygen where it’s needed for energy production, while nutrients travel in the plasma to fuel metabolism. The blood also transports waste products to be removed by the lungs or kidneys, but the central idea is the delivery of oxygen and nutrients to sustain cellular activity.

Other options point to things blood helps with, but they aren’t its main purpose. Producing hormones happens in glands, not in the blood itself, though hormones travel in the blood. Filtering waste is done by organs like the kidneys; blood carries waste but doesn’t filter it. Regulating temperature involves blood flow, but that’s a secondary effect of circulation, not the primary function.