Name the three types of toxic agents.

• A. Chemical, Physical, Biological
• B. Biological, Chemical, Genetic
• C. Physical, Chemical, Nutritional
• D. Chemical, Biological, Environmental

Answer: (A)

Toxic agents are categorized by what they are, yielding three broad types: chemical, physical, and biological. This framework fits because each category describes a distinct kind of hazard: chemical toxins are substances like heavy metals, solvents, or pesticides that cause harm through their chemical interactions in the body; physical toxins are hazards arising from physical factors such as ionizing radiation, extreme temperatures, or high levels of noise that damage tissues or disrupt function; biological toxins are toxic substances produced by living organisms, such as bacterial or plant toxins and venom.

Examples help ground the idea: chemical toxins include lead, mercury, or formaldehyde; physical toxins include radiation or extreme heat/cold; biological toxins include botulinum toxin, ricin, or snake venom.

Why the other options don’t fit as the standard three categories: genetic concepts refer to changes in DNA rather than a broad class of toxic agents; nutritional factors aren’t a primary category of toxic agents themselves, though nutrition can influence toxicity; environmental is a contextual source of risk rather than a strict agent type. The three fundamental categories that best capture the nature of toxic agents are chemical, physical, and biological.