Which of the following describes how polymers interact when added to solutions?

Polymers interact with solutions primarily through a process known as thickening. When added to a solvent, polymers can increase the viscosity of the solution, meaning that they make it thicker. This occurs because polymers consist of long chains of molecules that entangle in the solvent, disrupting the flow of the liquid. As the concentration of the polymer increases, the interactions among these large molecules and the solvent lead to a significant increase in the solution's thickness.

This thickening effect is particularly useful in various applications, such as in aquatic pest control, where it may help in maintaining the dispersion of active ingredients, ensuring they remain effective for longer periods on the surfaces they are intended to treat.

The other options do not accurately describe the typical behavior of polymers in solution. While certain conditions might lead to reduced flow or altered interactions, the fundamental property of polymers in solution is their ability to increase viscosity rather than separating components or enhancing volatility.