True or False: Most fuels must liberate fuel gases or vapors for ignition to occur.

The statement is indeed true because the majority of fuels need to release fuel gases or vapors for ignition to take place. This is a fundamental concept in fire science known as the "vaporization" of fuels, which indicates that most combustible substances must transition to a gaseous state to mix with air and ignite.

For example, liquids such as gasoline or alcohol must vaporize to form an explosive mixture with air before ignition can occur. Similarly, solid fuels like wood release gas when heated, which then ignites and sustains a fire. The process of pyrolysis in solid fuels describes how heat breaks down the material producing flammable vapors.

Although some solid fuels can ignite directly, the practicality of most fires and combustion processes shows that gases must be present for sustained combustion, hence making the assertion correct in the context of common fire behavior scenarios.

Options suggesting that this condition only applies to solid fuels or that it varies with material overlook the broader principle that ignition largely depends on the vaporization and mixing of gases with air for a significant number of fuels used in fires.