When air is heated enough so that it is warmer than the surrounding air, it is?

To be "unstable", the lowest layers of an air mass must be so warm and/or humid that, if some of the airrises, then that air parcel is warmer than its environment, and so it continues to rise. This is called moist convection.

The answer is Unstable air

Answer it orbits high above earth to gain clearer images of light, it magnifies images relative to the human eye, it records most of the universe as it was in the past, not as it is now;