Which of the following is NOT a type of front?

The type identified as "Fog Front" is not recognized as an official category of weather front in meteorological terminology. In weather science, a front is defined as a boundary separating two masses of air that have different densities, often associated with changes in temperature and humidity. The primary types of fronts include cold fronts, warm fronts, and occluded fronts, which specifically refer to the interactions of different air masses.

A cold front occurs when a mass of cold air displaces warmer air. This often leads to more severe weather conditions, including thunderstorms. A warm front, on the other hand, occurs when warm air moves over cold air, commonly resulting in gradual weather changes rather than abrupt ones. An occluded front is formed when a cold front overtakes a warm front, leading to complex weather patterns and changes.

While fog can occur in relation to fronts, particularly when warm, moist air meets cooler surfaces, it does not constitute a type of front itself. Thus, recognizing the correct meteorological definitions and types of fronts clarifies why "Fog Front" is not valid in this context.