The gaseous portion of outer earth surface is

Options

A. Hydrosphere
B. Atmosphere
C. Lithosphere
D. Biotic component.

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks about the gaseous portion of the outer surface of the Earth. We need to identify which layer or component of the Earth is primarily composed of gases.

2. **Identify the Options**: The options provided are:
- Hydrosphere
- Atmosphere
- Lithosphere
- Biotic components

3. **Analyze Each Option**:
- **Hydrosphere**: This refers to all the water bodies on Earth, including oceans, rivers, and lakes. It does not pertain to gases, so this option is incorrect.
- **Atmosphere**: This is the layer of gases that surrounds the Earth. It acts like an envelope and contains various gases, making it the correct answer.
- **Lithosphere**: This refers to the solid, rocky outer layer of the Earth. It does not contain gases, so this option is also incorrect.
- **Biotic Components**: This term refers to living organisms. While they may interact with gases, they are not themselves a gaseous component, making this option incorrect as well.

4. **Conclusion**: Based on the analysis, the gaseous portion of the outer Earth’s surface is the **Atmosphere**. This layer is primarily composed of nitrogen (about 78%) and oxygen (about 21%).

5. **Final Answer**: The gaseous portion of the outer Earth's surface is the **Atmosphere**.

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