Explanation/Reference:
Explanation:
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires.
The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elements are present and combined in the right mixture, meaning that fire is actually an event rather than a thing. A fire can be prevented or extinguished by removing any one of the elements in the fire triangle. For example, covering a fire with a fire blanket removes the oxygen part of the triangle and can extinguish a fire.
The fire tetrahedron represents the addition of a component, the chemical chain reaction, to the three already present in the fire triangle. Once a fire has started, the resulting exothermic chain reaction sustains the fire and allows it to continue until or unless at least one of the elements of the fire is blocked. Foam can be used to deny the fire the oxygen it needs. Water can be used to lower the temperature of the fuel below the ignition point or to remove or disperse the fuel. Halon can be used to remove free radicals and create a barrier of inert gas in a direct attack on the chemical reaction responsible for the fire.
Incorrect Answers:
B: CO2 is not one of the four basic elements of fire. CO2 is a fire suppressant. Therefore, this answer is incorrect.
C: Wood is not one of the four basic elements of fire. Wood would be an example of the 'fuel' element of fire. Therefore, this answer is incorrect.
D: Flame is not one of the four basic elements of fire. Flame is just another name for fire. Therefore, this answer is incorrect.
References:
https://en.wikipedia.org/wiki/Fire_triangle