What is the body's transport system called?

• A. Cardiovascular System
• B. Digestive System
• C. Nervous System
• D. Endocrine System

Answer: (A)

The body's transport system is the cardiovascular system—the network of the heart, blood vessels, and blood that moves substances around the body. It ferries oxygen from the lungs to tissues, carries carbon dioxide back to the lungs to be exhaled, transports nutrients from the gut to cells, and distributes hormones to their targets. It also helps regulate temperature and supports immune responses through blood components like white blood cells.

The other systems have different primary roles: the digestive system breaks down food and absorbs nutrients; the nervous system uses electrical signals for rapid communication; the endocrine system produces hormones—often traveling in blood—but the thorough, circulating transport of these substances is the job of the cardiovascular system.