What is a key characteristic of an oxidizer?

An oxidizer is a substance that can yield oxygen readily and stimulate combustion, making it a critical component in many chemical reactions, particularly those involving fire. By providing oxygen, an oxidizer enhances the process of combustion, often increasing the intensity and speed of a fire. This characteristic is essential for understanding the role of oxidizers in hazardous materials situations, as they can significantly alter the dynamics of a fire.

The other options do not accurately describe the nature of oxidizers. Preventing combustion, being exclusively a liquid, and having no impact on fire behavior do not align with the fundamental characteristics of oxidizers, which are known for their ability to support and accelerate combustion rather than inhibit it. Therefore, recognizing an oxidizer's role in enhancing combustion is vital for safety and management when handling hazardous materials.