What serves as the primary transport media for all substances moving around the body?

The primary transport medium for all substances moving around the body is blood. Blood is responsible for delivering essential nutrients, oxygen, hormones, and other vital substances to various cells and tissues throughout the body. It also plays a critical role in removing waste products from metabolism, such as carbon dioxide and urea.

While water is essential for many bodily functions, it is not the primary transport medium itself. It serves as a solvent that aids in the transport of substances within the blood and other bodily fluids. Blood comprises a large percentage of water, but it is the combination of plasma, red blood cells, white blood cells, and platelets that collectively function as the transport system.

Air, while important for respiration, does not circulate throughout the body in the same way that blood does. It is primarily involved in the exchange of gases (oxygen and carbon dioxide) in the lungs.

Sweat primarily serves as a means for thermoregulation and does not have a role in transporting nutrients or waste products throughout the body.

Overall, blood is the comprehensive transport system that fulfills the body's needs by moving a variety of substances where they are required, making it the central medium for transportation in biological systems.