Final answer:
CFCs need a chlorine atom, UV radiation, and ozone molecules to destroy ozone.
Step-by-step explanation:
The destruction of ozone by CFCs requires three conditions: the presence of a chlorine atom (Cl), exposure to UV radiation, and the availability of ozone molecules (O3). When CFCs are exposed to UV light in the stratosphere, a chlorine atom is released from the CFC molecule. This free chlorine atom then reacts with an ozone molecule, leading to the destruction of ozone and the formation of chlorine monoxide (ClO) and molecular oxygen (O2).