Final answer:
Toxicology is the study of how different agents can cause harm to living organisms. Controlled substances are categorized into narcotics, hallucinogens, and stimulants. Examples of narcotics are heroin and oxycodone, hallucinogens include LSD and psilocybin mushrooms, and stimulants include cocaine and amphetamines.
Step-by-step explanation:
Toxicology is the study of the adverse effects of chemical, physical, or biological agents on living organisms and the ecosystem. It focuses on understanding how various agents can cause harm and finding ways to prevent and ameliorate these effects. There are different categories of controlled substances, including narcotics, hallucinogens, and stimulants. Examples of narcotics include heroin and oxycodone, hallucinogens include LSD and psilocybin mushrooms, and stimulants include cocaine and amphetamines.