The effects of a biological attack may not be immediately visible at a scene. which group would likely be the first to observe the indications of an attack?

The only people who would be able to detect the situation is a chemical warfare agent. There are many categories of expertise on the type of chemical used. It depends on the physical reaction that happens in or on the body. These are some of them; tear agents, vomiting agents, malodorants, incapacitating agents, psychological agents, blood agents and nerve agents.