Biosphere is

Options

A. a component in the ecosystem
B. composed of the plants present in the soil
C. life in the outer space
D. composed of all living organisms present on earth which interact with the physical environment

Answer

**Step-by-Step Solution:**

1. **Understanding the Concept of Biosphere:**
- The biosphere is the global sum of all ecosystems. It is a closed system and largely self-regulating. The biosphere is where life exists on Earth, encompassing all living organisms and their interactions with the physical environment.

2. **Hierarchy of Biological Organization:**
- To understand the biosphere, it's essential to recognize the hierarchy of biological organization:
- **Individual:** The smallest unit, representing a single organism.
- **Population:** A group of individuals of the same species living in a specific area.
- **Community:** Different populations interacting with each other in a particular environment.
- **Ecosystem:** A community of living organisms and their physical environment interacting as a system.
- **Biome:** A large area characterized by specific climate conditions and particular types of plants and animals.
- **Biosphere:** The highest level, encompassing all biomes and ecosystems on Earth.

3. **Defining the Biosphere:**
- The biosphere includes all living organisms (plants, animals, microorganisms) and their interactions with the non-living components of the environment (air, water, soil). It is not just a component of an ecosystem; rather, it is the sum of all ecosystems.

4. **Analyzing the Options:**
- Given the options, we need to identify which one correctly defines the biosphere:
- **A:** A component in an ecosystem - Incorrect, as the biosphere is not just a component but encompasses all ecosystems.
- **B:** Composed of plants present in the soil - Incorrect, as it does not include all living organisms.
- **C:** Life in the outer space - Incorrect, as the biosphere pertains to life on Earth.
- **D:** Composed of all living organisms present on Earth which interact with the physical environment - Correct, as it accurately describes the biosphere.

5. **Conclusion:**
- The correct answer is **D**: The biosphere is composed of all living organisms present on Earth which interact with the physical environment.

---