Which one of the following is not a green houses gas ?

Options

A. `CO_(2)`
B. `CH_(4)`
C. `O_(2)`
D. CFCs.

Answer

To determine which of the following is not a greenhouse gas, we need to analyze the options provided: carbon dioxide, methane, oxygen, and CFCs (chlorofluorocarbons).

### Step-by-Step Solution:

1. **Understanding Greenhouse Gases**:
- Greenhouse gases are substances that trap heat in the atmosphere and contribute to the greenhouse effect, which leads to global warming. Common greenhouse gases include carbon dioxide (CO2), methane (CH4), and chlorofluorocarbons (CFCs).

2. **Analyzing the Options**:
- **Carbon Dioxide (CO2)**: This is a well-known greenhouse gas that is produced by burning fossil fuels and deforestation. It contributes significantly to the greenhouse effect.
- **Methane (CH4)**: This is another potent greenhouse gas, emitted during the production and transport of coal, oil, and natural gas, as well as from livestock and other agricultural practices.
- **Oxygen (O2)**: While essential for life, oxygen does not trap heat in the atmosphere and does not contribute to the greenhouse effect.
- **CFCs (Chlorofluorocarbons)**: These are man-made compounds that also act as greenhouse gases, contributing to ozone depletion and global warming.

3. **Conclusion**:
- Among the options provided, oxygen is the only gas that does not contribute to the greenhouse effect. Therefore, the answer to the question "Which one of the following is not a greenhouse gas?" is **Oxygen**.

### Final Answer:
**Oxygen is not a greenhouse gas.**

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