Question

the natural destruction of ozone over antarctica occurs when _______.

o the stable low - pressure system is replaced by a high - pressure system
o temperatures drop low enough for clouds to form between 10 and 30 km up in the atmosphere
o the stable higher - pressure system is replaced by a low - pressure system
o temperatures in the antarctic increase above the freezing point at 20 to 40 km up in the atmosphere

Explanation:

In the Antarctic, when temperatures drop low enough for clouds (polar - stratospheric clouds) to form between 10 - 30 km in the atmosphere, chemical reactions on the surface of the cloud particles can lead to the natural destruction of ozone. These clouds provide a surface for chlorine - containing compounds to be converted into more reactive forms that can break down ozone.

Answer:

temperatures drop low enough for clouds to form between 10 and 30 km up in the atmosphere