What is the common characteristic of emulsifiable concentrates?

Emulsifiable concentrates are a type of pesticide formulation that typically contains active ingredients dissolved in an organic solvent, alongside emulsifiers to create a stable emulsion when mixed with water. The key characteristic of these formulations is that they often require a surfactant or emulsifier to facilitate the mixing process and ensure a uniform dispersion in water. By incorporating emulsifiers, emulsifiable concentrates enable the active ingredients to produce an effective pesticide solution that can be easily applied.

The other options do not reflect the nature of emulsifiable concentrates. They are not always granular, as these formulations are typically in liquid form. While they can have varying concentrations, the idea that they have very low concentrations does not accurately represent the essence of emulsifiable concentrates. Lastly, these concentrates are not primarily solids, as their defining feature is that they are liquid formulations that emulsify when combined with water. Therefore, the necessity of a surfactant for mixing is central to the functionality and use of emulsifiable concentrates.