The sky becomes clear. Rain or snow begins to fall. Cold air is pushed to high altitudes. Warm air is pushed to ground level.
I gave my students this multiple choice question: What most likely happens when a cold air mass comes into contact with a warm, moist air mass?

Only one answer is correct among these 4 choices:
- The sky becomes clear.
- Rain or snow begins to fall.
- Cold air is pushed to high altitudes.
- Warm air is pushed to ground level.

Could you tell me which one is correct?

Rain or snow begins to fall.