Final answer:
Viscosity generally remains constant throughout a liquid and is not impacted by surface-layer phenomena such as surface tension. The cohesive forces that cause surface tension do not affect the viscosity of the fluid at the surface layers, which is instead affected by temperature changes.
Step-by-step explanation:
The viscosity of a fluid is not maximum at the layers adjacent to the surface but rather is generally constant throughout the fluid unless temperature or other factors vary within the fluid. Viscosity is the fluid's resistance to flow and is influenced by the internal cohesive forces between molecules. The surface tension of a liquid, however, is a separate phenomenon that does occur at the surface and is a result of cohesive forces pulling the surface molecules inward, creating a minimized surface area and acting like a stretched film over the liquid. This is different from viscosity and does not mean that viscosity is higher at the surface.
In fact, viscosity is often seen as consistent throughout a liquid. However, areas closer to solid boundaries can sometimes experience what's known as the no-slip condition, where the fluid velocity relative to the boundary is zero; this is due to friction between the fluid and the boundary but does not imply a change in viscosity. Changes in viscosity are more commonly due to temperature variations, with higher temperatures generally decreasing the viscosity of a liquid by lessening the effects of cohesive forces.