What is one consequence of the concentration of oxygen being below the necessary level for combustion?

When the concentration of oxygen falls below the necessary level for combustion, the consequence is that combustion cannot occur, leading to no combustion. Fire requires a certain percentage of oxygen in the atmosphere to sustain a chemical reaction with a fuel source. Typically, this threshold is around 16% oxygen by volume, while normal air contains approximately 21% oxygen. When oxygen levels drop significantly below this threshold, the fuel source lacks sufficient oxidizer to support the combustion process, resulting in the complete absence of fire. This principle is important in fire investigations, as understanding the environmental conditions that may lead to fire suppression helps inform strategies for fire prevention and control.

The other options suggest outcomes that are associated with combustion conditions rather than the lack of necessary oxygen. Increased combustion efficiency, delayed ignition, and enhanced fire dynamics all imply some degree of combustion activity, which would not occur if the oxygen concentration is insufficient.