Which of the following best describes a pesticide that exhibits chronic toxicity?

The description of chronic toxicity refers to the potential for a substance, such as a pesticide, to cause long-term health effects as a result of repeated exposure over time. This type of toxicity does not necessarily lead to immediate or acute symptoms, but instead, the harmful effects may develop slowly and could become apparent only after an extended period of exposure, often involving lower doses.

Chronic toxicity is particularly concerning in the context of agricultural workers or communities who may come into regular contact with pesticides. These long-term effects can manifest in various ways, such as respiratory issues, cancers, or neurological problems, depending on the specific chemical involved.

In contrast, the other options focus on characteristics that do not align with the concept of chronic toxicity. For instance, acute toxicity is characterized by immediate effects from a single exposure, while high doses usually relate more to acute toxicity rather than chronic effects. The statement that a substance has no known effects does not apply to chronic toxicity, as this implies that the substance is entirely benign, which undermines the core concept of chronic toxicity.

Thus, the correct answer accurately captures the essence of chronic toxicity and its implications for health based on repeated exposure to a pesticide.