The term "choking agent" mainly refers to which type of effect?

The term "choking agent" primarily refers to substances that primarily injure victims through respiratory failure. Choking agents are a category of chemical agents that target the respiratory system, causing damage to lung tissues and leading to symptoms such as difficulty breathing, choking sensations, and ultimately respiratory failure. These agents can disrupt normal respiration and lead to hypoxia due to the body's inability to take in or use oxygen effectively.

In contrast, the other options pertain to different types of chemical warfare agents. For instance, substances that cause severe skin lesions are typically classified as blister agents. Agents that directly attack the nervous system are known as nerve agents, which disrupt normal neurotransmission. Blocking blood circulation is characteristic of certain types of chemical agents that affect the blood or circulatory system, such as cyanides. Each of these categories operates differently, but choking agents specifically focus on impeding the respiratory function.