What is true about oxygen in terms of combustion?

Oxygen plays a crucial role in the process of combustion. It supports combustion by being one of the three essential components of the fire triangle, which includes fuel, heat, and an oxidizing agent—in this case, oxygen. Without sufficient oxygen, a fire cannot ignite or sustain itself. When oxygen comes into contact with a combustible material and heat, it catalyzes the chemical reaction that leads to burning.

In contrast, the other options present misunderstandings about the role of oxygen. While it is vital for combustion, it does not burn on its own; rather, it facilitates the burning of other materials. Oxygen doesn't extinguish fires; in fact, it is the opposite—it promotes and sustains them. Furthermore, while oxygen is essential for the combustion process, it is not a fuel source itself; rather, fuels are the substances that undergo combustion in the presence of oxygen. Thus, recognizing oxygen as a supporter of combustion is key to understanding fire behavior and firefighting strategies.