Application of water to the base of a fire with a straight stream or solid stream is a(n) __________ attack.

The application of water to the base of a fire using a straight stream or solid stream is categorized as a direct attack. This method is effective because it targets the seat of the fire— the most intense portion— directly. By applying water in a straight or solid stream, firefighters can cool the burning material quickly, reducing the temperature and suppressing the combustion.

In a direct attack, the goal is to extinguish the fire where it is burning, as this provides the best chance of quickly bringing the situation under control. This approach often allows firefighters to combat the flames more efficiently, as opposed to indirect methods, where water is applied to cooler surfaces or surrounding areas to create steam and drive heat away from the fire.

Combining these techniques may be effective in certain scenarios, but the key attribute of a direct attack is the immediate interaction of water with the flames themselves, making the application of a solid or straight stream the most effective means of extinguishing the fire at its source.