Which of the following are green house gases ? (a) `CO_2` (b) `O_2` (c) `O_3` (d) CFC (e) `H_2O`

Options

A. a,b,d
B. a,b,c,d
C. a,c,d
D. a,c,d,e

Explanation

To determine which of the given gases are greenhouse gases, we need to analyze each option based on their properties and their ability to absorb infrared (IR) radiation.

### Step-by-Step Solution:

1. **Identify Greenhouse Gases**: Greenhouse gases are those that can absorb and emit infrared radiation, contributing to the greenhouse effect and global warming.

2. **Analyze Each Option**:
- **(a) CO₂ (Carbon Dioxide)**:
- CO₂ is a well-known greenhouse gas. It absorbs IR radiation and is a significant contributor to global warming.
- **Conclusion**: CO₂ is a greenhouse gas.

- **(b) O₂ (Oxygen)**:
- O₂ does not absorb IR radiation effectively. It is not considered a greenhouse gas.
- **Conclusion**: O₂ is not a greenhouse gas.

- **(c) O₃ (Ozone)**:
- Ozone in the stratosphere absorbs UV radiation and some IR radiation, making it a greenhouse gas.
- **Conclusion**: O₃ is a greenhouse gas.

- **(d) CFC (Chlorofluorocarbons)**:
- CFCs are synthetic compounds that can absorb IR radiation and contribute to both greenhouse effect and ozone depletion.
- **Conclusion**: CFCs are greenhouse gases.

- **(e) H₂O (Water Vapor)**:
- Water vapor is the most abundant greenhouse gas in the atmosphere, as it can absorb a wide range of IR radiation.
- **Conclusion**: H₂O is a greenhouse gas.

3. **Summarize the Findings**:
- From the analysis, the greenhouse gases among the options are:
- (a) CO₂
- (c) O₃
- (d) CFC
- (e) H₂O

4. **Final Answer**:
- The greenhouse gases from the given options are **(a) CO₂, (c) O₃, (d) CFC, and (e) H₂O**.