Which term refers to the upward force on the body when immersed in water?

The term that refers to the upward force on the body when immersed in water is buoyancy. This concept is rooted in Archimedes' principle, which states that an object submerged in a fluid experiences an upward force equal to the weight of the fluid it displaces. As a result, buoyancy plays a critical role in hydrotherapy and aquatic therapy environments, where individuals benefit from reduced weight-bearing stress on their joints and improved mobility due to this upward force.

In contrast, hydrostatic pressure refers to the pressure exerted by a fluid due to its weight; it increases with depth but does not specifically denote the upward force on an object. Specific gravity measures the density of a substance compared to the density of water and does not describe the force experienced when submerged. Total drag force relates to the resistance an object experiences as it moves through water, which is a distinct concept from the buoyant force acting on the object. Therefore, buoyancy is the correct term associated with the upward force experienced when a body is immersed in water.