How is 'toxicity' defined in relation to chemical substances?

The definition of 'toxicity' in relation to chemical substances centers around the adverse effects these substances can have on living systems. Understanding toxicity involves recognizing that it is not merely the presence of a substance, but how that substance interacts with biological entities, potentially causing harm to health or the environment.

Toxicity is determined by factors such as the chemical nature of the substance, the dose, and the route of exposure, all of which can influence the severity of the effects. For instance, a substance that might be harmless in small amounts could become toxic at higher concentrations or with prolonged exposure. This definition aligns with regulatory and safety practices, which emphasize the importance of assessing risks associated with chemical substances.

Other options provided do not accurately capture the concept of toxicity. The weight of a substance, its frequency of exposure, or its physical characteristics like color and texture do not determine its toxicity directly. What matters is how this substance interacts with the biological systems it contacts, leading to potential adverse effects.