How do chlorofluorocarbons (CFCs) contribute to ozone depletion?

Ultraviolet light breaks down CFCs in the stratosphere, releasing chlorine atoms. A chlorine atom reacts with an ozone molecule (O₃), breaking it apart into oxygen (O₂) and chlorine monoxide; the chlorine can then be regenerated and destroy more ozone. So choice A, “chlorine atom (Cl) breaks apart the ozone molecule,” is correct. CFCs do not deplete ozone simply by blocking its filtering effects.

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