Which of the following is not a greenhouse gas?

Options

A. Carbon dioxide
B. Sulphur dioxide
C. Methane
D. Nitrogen

Answer

To determine which of the following is not a greenhouse gas, we need to understand what greenhouse gases are and identify the options provided.

### Step-by-Step Solution:

1. **Understand Greenhouse Gases**: Greenhouse gases are substances in the atmosphere that trap heat. They allow sunlight to enter the atmosphere but prevent some of the heat from escaping back into space. Common greenhouse gases include carbon dioxide (CO2), methane (CH4), and sulfur dioxide (SO2).

2. **Identify the Options**: The question implies that there are multiple options to choose from. Let's assume the options include:
- A) Carbon Dioxide (CO2)
- B) Methane (CH4)
- C) Sulfur Dioxide (SO2)
- D) Nitrogen (N2)

3. **Analyze Each Option**:
- **Carbon Dioxide (CO2)**: This is a well-known greenhouse gas that contributes to the greenhouse effect.
- **Methane (CH4)**: Another significant greenhouse gas, much more effective than CO2 at trapping heat.
- **Sulfur Dioxide (SO2)**: While it can have some warming effects, it is primarily known for causing acid rain and is not a major greenhouse gas.
- **Nitrogen (N2)**: This is a major component of the atmosphere but does not trap heat and is not considered a greenhouse gas.

4. **Conclusion**: Based on the analysis, Nitrogen (N2) is not a greenhouse gas. Therefore, the answer to the question is:
- **Answer**: Nitrogen (N2) is not a greenhouse gas.

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