An air mass is a large body of air with uniform temperature and

uniform thickness
uniform moisture
low pressure throughout
abundant condensation nuclei

I would say the correct answer would be uniform moisture. Air masses are very large areas that are flat where its characteristics adapts to the surface underneath them. It has uniform temperature and uniform humidity. Hope this helps.

D.haka is the first answer and a.canberra is the second answer

Ibelieve it is the 2nd answer, create gardens on all rooftops. let me know if this .