Which factor does not typically change when an adjuvant is added to a pesticide mixture?

When an adjuvant is added to a pesticide mixture, it generally alters certain characteristics of the mixture, but the toxicity of the pesticide itself remains unchanged. Adjuvants are substances that enhance the pesticide's performance, and they can improve aspects such as surface tension and viscosity, which affect how the pesticide spreads and adheres to surfaces.

While the effectiveness of a pesticide might increase due to better adherence or increased absorption facilitated by the adjuvant, the inherent toxicity of the pesticide—its ability to cause harm or damage to organisms—does not change as a direct result of adding an adjuvant. The fundamental chemical properties of the active ingredient, including its toxicity, stay the same, meaning that the risk associated with the pesticide remains consistent, regardless of any enhancements brought about by the adjuvant. This is why the correct response identifies toxicity as the factor that does not typically change with the addition of an adjuvant.