Which of the following is a characteristic of conventional pesticides?

Conventional pesticides are often designed to be broad-spectrum, meaning they have the potential to affect a wide variety of organisms beyond just the intended pest species. This characteristic can lead to unintended consequences in ecosystems, as these chemicals may harm beneficial insects, wildlife, and plants that are not the pests being targeted.

In contrast, the other options highlight attribute characteristics that do not typically align with conventional pesticides. For instance, while some conventional pesticides may break down over time, they are generally not considered environmentally friendly or fully biodegradable. Similarly, the idea of being highly specific to a single pest is more aligned with biological or targeted pest control strategies rather than conventional pesticides, which often aim to manage multiple pests simultaneously. Lastly, the notion that conventional pesticides do not necessitate safety precautions during application is misleading, as they often require rigorous safety protocols to protect both the applicator and the environment from potential hazards. Thus, the defining characteristic of broad-spectrum effects solidifies the correctness of the chosen answer.