`CO_2` is found in which layer of atmosphere?

Options

A. Thermosphere
B. Mesosphere
C. Troposphere
D. Stratosphere

Answer

To determine in which layer of the atmosphere carbon dioxide (CO2) is found, we can analyze the different layers of the atmosphere and their characteristics.

### Step-by-Step Solution:

1. **Identify the Layers of the Atmosphere**:
- The atmosphere is divided into several layers:
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
- Exosphere

2. **Understand the Characteristics of Each Layer**:
- **Troposphere**: This is the lowest layer of the atmosphere where weather occurs, and it contains most of the atmosphere's mass. It is also where harmful gases, including CO2, are concentrated.
- **Stratosphere**: Located above the troposphere, this layer contains the ozone layer, which protects us from harmful UV radiation. It has very little vertical mixing, which means gases do not accumulate here like in the troposphere.
- **Mesosphere**: This layer is above the stratosphere and is where meteors burn up upon entering the atmosphere. It is less dense and does not contain significant amounts of CO2.
- **Thermosphere**: This layer is very high up and is characterized by a significant increase in temperature. It contains very few gas molecules, including CO2.
- **Exosphere**: This is the outermost layer of the atmosphere, where the atmosphere transitions into outer space. It has extremely low density and very few gas molecules.

3. **Conclusion**:
- Based on the characteristics of these layers, CO2 is primarily found in the **troposphere**, as it is the layer closest to the Earth's surface where weather and atmospheric phenomena occur.

### Final Answer:
CO2 is found in the **troposphere**.

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