Explanation:

- Ozone formation in the atmosphere occurs mainly through a reaction that involves oxygen molecules (O2). This process is initiated by the action of certain types of radiation.

- Option 1: IR radiation

- Infrared (IR) radiation primarily adds heat to molecules. It is not energetic enough to split oxygen molecules and form ozone.

- Option 2: UV radiation

- UV radiation is the correct answer. It has the appropriate energy to break the O2 bonds, leading to ozone (O3) formation.

- The ultraviolet (UV) rays from the sun cause oxygen molecules to split and form ozone.

- Option 3: Gamma rays

- Gamma rays are extremely high energy and would likely break molecules apart entirely, beyond the formation of ozone.

- Option 4: X-rays

- X-rays are also high energy, but they penetrate deeper and do not typically interact at the atmospheric level needed for ozone formation.

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