Question

Question was provided via image upload.

Explanation:

For the first blank: Ozone protects Earth from most (about 90%) of the UV radiation (specifically UV - B and a portion of UV - A). For the second blank: Aerosol sprays (especially those with CFCs - Chlorofluorocarbons) release chemicals (like CFCs) which deplete the ozone layer. CFCs break down in the stratosphere, releasing chlorine atoms that catalytically destroy ozone molecules.

Answer:

First blank: most (or a large portion, commonly stated as "most" in basic explanations)
Second blank: CFCs (Chlorofluorocarbons) (or "chlorofluorocarbons" or "ozone - depleting substances")