Which of the following acts as a green house gas ?

Options

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

Answer

To determine which of the following acts as a greenhouse gas, we need to understand what greenhouse gases are and identify them among the options provided.

### Step-by-Step Solution:

1. **Definition of Greenhouse Gas**:
- A greenhouse gas is defined as a gas that absorbs and emits radiant energy within the thermal infrared range. This property allows these gases to trap heat in the atmosphere.

2. **Common Greenhouse Gases**:
- The primary greenhouse gases in Earth's atmosphere include:
- Water vapor (H2O)
- Carbon dioxide (CO2)
- Methane (CH4)
- Nitrous oxide (N2O)
- Ozone (O3)

3. **Identifying Options**:
- We need to look at the options given in the question (not provided here, but we assume common gases).
- For example, if the options are:
- A) Carbon Dioxide (CO2)
- B) Oxygen (O2)
- C) Nitrogen (N2)
- D) Methane (CH4)

4. **Analyzing Each Option**:
- **A) Carbon Dioxide (CO2)**: This is a well-known greenhouse gas that traps heat in the atmosphere.
- **B) Oxygen (O2)**: This is not a greenhouse gas; it does not significantly absorb infrared radiation.
- **C) Nitrogen (N2)**: This is also not a greenhouse gas; it is inert and does not contribute to the greenhouse effect.
- **D) Methane (CH4)**: This is another significant greenhouse gas, much more effective than CO2 at trapping heat.

5. **Conclusion**:
- Based on the analysis, the gases that act as greenhouse gases from the options provided are Carbon Dioxide (CO2) and Methane (CH4).

### Final Answer:
- The greenhouse gases among the options are **Carbon Dioxide (CO2)** and **Methane (CH4)**.