On earth all living organisms constitute:

Options

A. Community
B. Biome
C. Association
D. Biosphere

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the part of Earth that encompasses all living organisms. We need to identify the term that describes this collective area.

2. **Defining Key Terms**:
- **Living Organisms**: These include all forms of life such as plants, animals, fungi, and microorganisms.
- **Ecosystem**: A community of living organisms interacting with their environment.

3. **Identifying the Correct Term**: The term that describes the global sum of all ecosystems where living organisms interact is known as the **Biosphere**.

4. **Explaining the Biosphere**:
- The biosphere includes various components of Earth:
- **Atmosphere**: The layer of gases surrounding the planet.
- **Lithosphere**: The solid outer part of the Earth, including soil and rocks.
- **Hydrosphere**: All water bodies on Earth, including oceans, rivers, and lakes.
- The biosphere is essentially the zone of life on Earth, where all living organisms exist and interact with each other and their environment.

5. **Conclusion**: Therefore, all living organisms on Earth constitute the **Biosphere**.

6. **Selecting the Answer**: If options are provided (A, B, C, D), the correct answer is option D, which states "Biosphere".

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