Which term describes the ability of a fluid to provide an upward force on an object immersed in it?

The concept of buoyancy refers specifically to the upward force that a fluid exerts on an object immersed in it. This force results from the pressure difference between the top and the bottom of the submerged object, due to the weight of the fluid above it. When an object is placed in a fluid, the fluid pushes up against it; if the upward force (buoyant force) is greater than the weight of the object, the object will rise. Conversely, if the object's weight is greater, it will sink.

Buoyancy is crucial in understanding various principles in physics and biology, such as how aquatic organisms navigate water or how ships float. The other options describe different phenomena: lift pertains to the force experienced by an object moving through a fluid, hydrostatic pressure relates to the pressure exerted by a fluid at a given depth, and viscosity describes the internal friction in a fluid affecting its flow. Understanding buoyancy allows one to grasp critical concepts about object stability and movement in fluid environments.