The ozone layer is depleted by

Options

A. `SO_2`
B. `C_xH_y`
C. `NO`
D. `CFCs`

Answer

### Step-by-Step Solution

1. **Understanding Ozone Layer Depletion**: The ozone layer is a protective layer in the Earth's stratosphere that absorbs most of the Sun's harmful ultraviolet (UV) radiation. Depletion of this layer can lead to increased UV exposure, which can cause health and environmental issues.

2. **Identifying the Culprits**: The question lists several options:
- A) ASO2
- B) Hydrocarbons (CHO)
- C) NO (Nitric Oxide)
- D) CFCs (Chlorofluorocarbons)

3. **Analyzing Each Option**:
- **ASO2**: Not commonly associated with ozone depletion.
- **Hydrocarbons (CHO)**: While they can contribute to air pollution, they are not primary agents of ozone layer depletion.
- **NO (Nitric Oxide)**: This gas can react with ozone and convert it into oxygen (O2), thus contributing to ozone depletion.
- **CFCs (Chlorofluorocarbons)**: These are well-known for their role in ozone layer depletion. They release chlorine atoms in the stratosphere, which catalyze the breakdown of ozone (O3) into oxygen (O2).

4. **Conclusion**: Both CFCs and NO are significant contributors to the depletion of the ozone layer. Therefore, the correct answer to the question is:
- **C) NO**
- **D) CFCs**

### Final Answer
The ozone layer is depleted by CFCs and NO.

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