What does the term "surface tension" refer to in liquids?

Surface tension refers to the cohesive forces that occur at the surface of a liquid, which result in the surface behaving like a stretched elastic membrane. This phenomenon arises from the attraction between molecules at the surface of the liquid, which are pulled inward by molecules deeper within the liquid, resulting in a minimized surface area.

This cohesive force is what allows certain insects to walk on water and causes raindrops to form beads on a surface. It plays a critical role in various physical phenomena and applications, such as capillary action, which is the ability of liquids to flow in narrow spaces without the assistance of external forces. The other options do not accurately define surface tension, as they refer to different properties or behaviors of liquids.