Which agents are primarily used in warfare and can have immediate lethal consequences?

The correct choice is primarily focused on nerve agents, which are a class of chemical warfare agents designed to disrupt the transmission of nerve impulses in the body. These agents act quickly upon exposure, often resulting in immediate and severe neurological effects that can lead to death within minutes. Nerve agents inhibit the enzyme acetylcholinesterase, which is essential for normal nerve function. As a result, acetylcholine builds up at nerve endings, leading to overstimulation of muscles, glands, and the central nervous system.

While other categories of agents, such as biological agents, radiological materials, and vesicants, can also be harmful and even lethal, their effects might not be as immediate as those caused by nerve agents. Biological agents often require a longer incubation period before symptoms appear, radiological materials might not cause immediate death but can have long-term health consequences, and vesicants cause damage over time through skin contact or inhalation. Hence, nerve agents are specifically designed for rapid lethality, making them particularly dangerous in warfare scenarios.