What does the term "toxic" refer to?

The term "toxic" specifically refers to substances that are harmful or lethal to living organisms due to the presence of toxins or poisons. This aligns with the fact that toxins can disrupt biological processes, leading to various adverse health effects in plants, animals, and humans. Understanding this concept is crucial in fields such as biology, environmental science, and medicine, where recognizing toxic substances can help in assessing ecological impacts and health risks.

In contrast, the other definitions provided are incorrect in this context. Benign or harmless relates to substances that do not cause harm, which is the opposite of toxic. Beneficial for growth characterizes substances that promote health and development rather than pose a threat. Stable and non-reactive refers to materials that do not easily undergo chemical reactions, again contrasting with the often reactive nature of toxic substances.