1. a cold air mass slides up under a warm air mass?

2. The sun warms the ground The warmed ground warms the air The warmed air rises?

3. A cumulonimbus cloud formed, and Water froze in the cloud moving high and low again and again?

4. land warmed the air above it The air rose and cooled down, dropping over the sea?

5. you tried to breathe high atop Mt. Everest?

6. warm, moist air moves in over a cold air mass?

7. frozen precipitation fell through a large mass of warmer than freezing air Then fell through a small mass of freezing air?

8. frozen precipitation fell through a small mass of warmer than freezing air Then fell through a larger mass of freezing air?

9. warm, moist air blew in from the ocean onto a coastal mountain?