What defines a toxin?

A toxin is defined as a chemical that has the ability to cause sickness and possibly death. This definition encompasses a wide range of substances that can be harmful to living organisms when introduced into the body. Toxins can disrupt biological processes, leading to various health effects, depending on their nature, dose, and route of exposure.

The option indicating that a toxin is a chemical that cannot cause illness is incorrect because it contradicts the fundamental definition of what a toxin is. Similarly, the characterization of a toxin as one that only affects the skin is too narrow, failing to account for the systemic effects that many toxins can have throughout the body. Lastly, stating that a toxin is a chemical used in medication misrepresents the concept, as medications are typically designed to promote health rather than cause harm, although they can be toxic at certain doses. Each wrong choice helps to underscore why the correct definition is vital for understanding the potential risks associated with chemical substances in our environment and workplaces.