Final answer:
Dry air sinks back into the center due to its higher density compared to the surrounding air. This is similar to how carbon dioxide sinks because of its higher density. Hot air, on the other hand, rises due to its lower density compared to the surrounding cool air.
Step-by-step explanation:
When dry air sinks back into the center, it is due to the difference in density between the dry air and the surrounding air. Dry air has a higher density than the surrounding air, so it sinks. This is similar to what happens with carbon dioxide, which also sinks due to its higher density than air. On the other hand, hot air rises because it has a lower density than the surrounding cool air.