Which system in the human body is responsible for transporting nutrients and oxygen?

The circulatory system is responsible for transporting nutrients and oxygen throughout the human body. This system consists of the heart, blood vessels (arteries, veins, and capillaries), and blood. The heart pumps oxygenated blood from the lungs to the rest of the body, delivering essential oxygen and nutrients to cells and tissues. Simultaneously, the circulatory system also returns deoxygenated blood back to the heart and lungs for reoxygenation and removal of carbon dioxide.

In contrast, the digestive system primarily focuses on breaking down food and absorbing nutrients into the bloodstream, but it does not directly transport these substances. The respiratory system is responsible for gas exchange, bringing in oxygen and removing carbon dioxide, while the excretory system focuses on eliminating waste products from the body. Thus, the circulatory system is the key player in the transportation of vital substances like nutrients and oxygen.