Complex sentence: Short-wavelength and mid-wavelength UV can cause much damage to living organisms, such that life on Earth outside of the deep oceans is possible only because the atmosphere, primarily the ozone layer, filters out nearly all short-wavelength and most mid-range UV.
Split into simpler sentences: Short-wavelength and mid-wavelength UV can cause much damage to living organisms. This means that life on Earth outside of the deep oceans is possible only because the atmosphere, primarily the ozone layer, filters out nearly all short-wavelength and most mid-range UV.