What happens to a warm air mass as it moves into an area occupied by a cold air mass?

When a cold air mass meets a warm air mass, a front is formed; if the cold air is replacing the warm air, it is known as a cold front. Cold fronts frequently cause rain showers or thunderstorms because they force air in a steep upward direction at the front's edge.

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When a cold air mass meets a warm air mass, a front is formed; if the cold air is replacing the warm air, it is known as a cold front. Cold fronts frequently cause rain showers or thunderstorms because they force air in a steep upward direction at the front's edge.

Maybe on the physical part? i dunno i just guessed plus i really need the points