Which of the following is true concerning the upward buoyant forces exerted by fluids?

The correct answer highlights that both gases and liquids exert upward buoyant forces. Buoyancy is the phenomenon that occurs when a fluid (which can be either a gas or a liquid) exerts an upward force on an object that is partially or fully immersed in it. This upward force arises from differences in pressure as a function of depth and is a result of the weight of the fluid displaced by the submerged object.

In the case of liquids, this principle is readily observed when objects float or sink in water, for instance. When an object is placed in a liquid, it displaces a volume of liquid equal to the volume of the submerged part of the object, and the buoyant force acting on it can be calculated using Archimedes' principle.

Similarly, gases also exert buoyant forces. For example, balloons rise in the air because the air (gas) exhibits buoyancy, allowing the helium or hot air inside the balloon—which is less dense than the surrounding air—to create an upward force. This shows that buoyancy is not restricted to just one type of fluid but is a property that applies to both gases and liquids.

The other options are limited in scope, focusing solely on one type of fluid or a specific characteristic of fluids,