Which category refers to the time between exposure and onset of symptoms?

• A. Onset effects
• B. Persistency
• C. Physical state
• D. Route of entry

Answer: (A)

The main idea here is the timing of when symptoms first appear after exposure—the onset of effects. Among the options, the term that best captures this idea is onset effects, because it directly points to when the effects begin after exposure.

Persistency is about how long a substance lasts or remains active, not when symptoms start. Physical state describes whether the substance is solid, liquid, or gas. Route of entry explains how the substance enters the body (inhalation, ingestion, dermal), not the timing of symptom appearance. So onset effects is the closest match for the concept of the time between exposure and the appearance of symptoms.