Which gas damage ozone layer?

Options

A. `CFC`
B. `O_2`
C. `Cl_2`
D. `CO_2`

Answer

### Step-by-Step Solution:

1. **Understanding the Ozone Layer**: The ozone layer is a region of Earth's stratosphere that contains a high concentration of ozone (O₃) molecules. It plays a crucial role in protecting life on Earth by absorbing the majority of the sun's harmful ultraviolet (UV) radiation.

2. **Identifying Harmful Gases**: Certain gases are known to contribute to the depletion of the ozone layer. These gases can break down ozone molecules, leading to a thinner ozone layer.

3. **Key Ozone-Depleting Substances**: The most significant gases that damage the ozone layer include:
- **Chlorofluorocarbons (CFCs)**: These are man-made compounds commonly used in refrigeration, air conditioning, and aerosol propellants.
- **Hydrochlorofluorocarbons (HCFCs)**: These are also used as substitutes for CFCs but still contribute to ozone depletion.
- **Methyl bromide**: This is used as a pesticide and is another harmful agent to the ozone layer.
- **Carbon tetrachloride (CCl₄)**: This compound was used in industrial applications and also contributes to ozone depletion.

4. **Conclusion**: Among the gases mentioned, **CFCs** are the most notorious for causing damage to the ozone layer. They are widely recognized as the primary culprits in ozone depletion.

### Final Answer:
The gas that damages the ozone layer is **Chlorofluorocarbons (CFCs)**.

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