Explanation:
Thunderstorms arise when layers of warm, moist air rise in a large, swift updraft to cooler regions of the atmosphere. There the moisture contained in the updraft condenses to form towering cumulonimbus clouds and, eventually, precipitation.
Answer:
compound
Explanation:
the first clause is linked with the second one using the coordinator "but", which form a compound sentence.
Is there a picture that can help us help you?
Answer:
The sea has waves. They go up and crash back down. You can think of this as hard times. When you think your doing good and start rising to the top you often crash back down. This (the crash) leads to difficulties or troubled times.
