Which variable does NOT influence toxicity of a substance?

The influence of toxicity from a substance is primarily tied to biological factors and individual health status rather than the physical environment. Gender plays a role because men and women can metabolize chemicals differently, leading to varied toxicity levels. Age is critical as younger and older individuals often have different physiological responses to toxic substances; children may be more susceptible due to their developing bodies, while the elderly may have compromised systems. Medical history can significantly affect how a person reacts to toxins, particularly if they have pre-existing conditions or allergies that alter their response.

Location, while it may impact the exposure levels to a toxin or the environmental context, does not fundamentally alter the inherent toxicity of a substance when considering it on an individual level. The inherent characteristics of the substance itself, in conjunction with the biological responses from gender, age, and health, are the primary factors that determine toxicity. Therefore, it is accurate to state that location does not influence the toxicity of a substance directly, distinguishing it from the other variables that do impact individual reactions.