What are the four classifications of chemical agents?

The four classifications of chemical agents are Nerve, Blood, Choking, and Blister. Each of these classifications refers to specific types of chemical warfare agents with distinct mechanisms of action and effects on the human body.

Nerve agents disrupt the transmission of nerve impulses, leading to severe physiological effects, often resulting in death if exposure is significant and not treated promptly. Blood agents, such as cyanides, interfere with the body's ability to use oxygen, effectively poisoning the blood. Choking agents, like chlorine gas, damage respiratory tissues and can lead to asphyxiation. Finally, blister agents, such as mustard gas, cause severe burns and blisters on the skin and mucous membranes.

These classifications are critical for understanding the nature of threats posed by chemical agents in military and tactical scenarios, as they guide the development of protective measures and medical responses. Other options present different categories of materials or hazards but do not align with the established classifications of chemical agents used in warfare and defense contexts.