Health & Safety Code Class 314 Practice Test 2026 - Free Health & Safety Questions and Study Guide

Understanding how drugs enter the body is key. The common four routes used to categorize drug abuse are ingestion (swallowing), inhalation (breathing in), topical application (skin or mucous membranes), and injection (directly into the body with a needle). The missing category here is the injectable route, which is distinct from swallowing, breathing in, or applying a substance to the skin. Transdermal is a specific topical method, intranasal is a form of inhalation, and oral is ingestion, so they don’t complete the set. That completes the four main abuse routes, making injection the best choice.