Answer:
air humidity
Step-by-step explanation:
Air parcel is a blob of air which moves in the atmosphere. For stability, if the air parcel is displaced vertically then it returns to the original position.
The most important points to know of the rising air parcel are the air humidity of the air, the temperature of the air and its dew point. These are the critical information to determine the stability of the air.
The air parcel rises buoyantly as it gets warmer than the surrounding environment.