Which type of exposure is characterized by immediate effects after a single event?

The correct choice is characterized by immediate effects that result from a single event or exposure. This type of exposure typically leads to rapid onset of symptoms or health effects, which can manifest just moments after the exposure occurs. For example, if a person is exposed to a toxic substance, they may experience symptoms like nausea, dizziness, or skin irritation almost immediately.

In contrast, chronic exposure refers to long-term exposure to a substance or condition that may result in gradual or delayed health effects over time. Contamination usually describes the presence of harmful substances in the environment, which may not point directly to a singular event. Persistent exposure refers to ongoing exposure to a harmful factor, often leading to cumulative effects.