What is a nerve agent?

A nerve agent is indeed a liquid agent that disrupts nerve impulses. These substances are highly toxic and act by interfering with the normal functioning of the nervous system. They inhibit enzymes that regulate neurotransmitters, leading to overstimulation of the nerves. This disruption can result in a range of symptoms, from muscle twitching and paralysis to respiratory failure and death, depending on the exposure level.

The other options do not accurately describe the characteristics or functions of nerve agents. Blister agents, for example, are known for causing severe skin blisters and are classified separately from nerve agents. Choking agents affect the respiratory system and cause difficulties in breathing, while biological weapons typically involve pathogens or toxins, which is distinct from the chemical mechanisms of nerve agents. This distinction is crucial in understanding the wide variety of agents used in warfare and their specific effects on human physiology.