Which of the following is an example of a heavy metal poison?

Lead is classified as a heavy metal poison due to its significant toxicity and accumulation in the body, particularly affecting the nervous system and other organs. Heavy metals are characterized by their high atomic weight and density, and they can cause toxic effects at even low concentrations. Lead, specifically, has recognized health impacts, especially in children, where it can lead to developmental issues and cognitive impairment.

In contrast, while arsenic and mercury are also toxic and can have severe health effects, they do not fall strictly under the commonly defined category of heavy metals as clearly as lead does. Fluoride, on the other hand, is not considered a heavy metal; it is a halogen and primarily associated with dental health issues in excessive amounts. Hence, lead stands out as a clear example of a heavy metal poison in this context.