Final answer:
Fire is a chemical process caused by combustion, which requires a mixture of a fuel, oxygen from the air, and source of ignition to produce flames. Water can suppress fire by reducing fuel moisture, not create it.
Step-by-step explanation:
Fire is the result of a chemical process known as combustion. When a fuel like wood, coal, or natural gas undergoes combustion, it reacts with oxygen in the air and releases energy in the form of light and heat. The correct answer is B) Chemicals mixed together, since the chemicals in this context are the oxygen from the air and the fuel. Combustion is a nonreversible reaction where the products, typically carbon dioxide and water, do not return to their original state. Key elements necessary for combustion include fuel, oxygen, and a source of ignition, all of which are part of the 'fire triangle' to cause burning. A lack of water isn't directly related to the creation of fire; rather, the presence of water can suppress or prevent fire by decreasing fuel moisture, which is necessary for combustion.