Which of the following describes the characteristics of a cyclone?

The characteristics of a cyclone are defined by a rotating air mass around a low-pressure center. Cyclones form when there is a significant difference in atmospheric pressure, leading to the movement of air. As air converges towards the low-pressure area, it begins to spiral due to the Coriolis effect, creating a characteristic cyclone structure with distinct wind patterns.

In contrast, the other options describe phenomena that do not align with the definition of a cyclone. High-pressure systems are typically associated with calm and clear weather, not the turbulent conditions found in cyclones. Stable air with no precipitation refers to anticyclonic conditions, which are the opposite of cyclonic activity. A rapid drop in temperature and humidity might indicate a passing weather front rather than the development of a cyclone, which usually brings increased precipitation and chaotic wind systems. Thus, the essence of a cyclone is its rotation around a low-pressure center, which distinguishes it from other meteorological phenomena.