What characterizes a cold front?

A cold front is characterized by the rapid movement of cold air masses that displace warm air ahead of them. When the cold air advances, it forces the warmer air to rise quickly, leading to the development of clouds and precipitation in the form of thunderstorms or heavy rain. This swift change in air masses often results in sudden drops in temperature, changes in wind direction, and can cause significant weather phenomena, including low visibility conditions.

Options that describe slow-moving air or steady rainfall with warm temperatures do not align with the dynamics of a cold front. Cold fronts are typically associated with more aggressive weather changes, rather than gentle rain or gradual temperature changes, which are characteristics of warm fronts or other weather systems. Thus, the distinguishing features of a cold front include its fast movement and the abrupt weather changes it brings, making the choice regarding fast-moving cold air the accurate representation of this meteorological phenomenon.