Although not directly toxic to living organisms, chlorofluorocarbons (CFCs)have had unanticipated impacts on the atmosphere. The ecological impacts of CFCs will be

A)relatively benign because even as secondary pollutants their toxicity remains low.
B)limited to the terrestrial ecosystem only.
C)limited to high-altitude communities where ultraviolet radiation is more intense.
D)uniformly serious, with effects experienced in almost all ecosystems and trophic levels.