A biosphere is composed of

Options

A. Living organisms
B. Living organisms _ Lithosphere
C. Living organisms +lithosphere + atmosphere
D. Living organisms +lithosphre +atmosphere+hydrosphere,

Answer

To answer the question "A biosphere is composed of," we can break it down into the following steps:

### Step 1: Understanding the Definition of Biosphere
The biosphere refers to the global sum of all ecosystems. It is the zone of life on Earth, a closed system, and largely self-regulating.

### Step 2: Identifying Components of the Biosphere
The biosphere is composed of several key components:
1. **Living Organisms**: This includes all forms of life such as plants, animals, fungi, and microorganisms.
2. **Lithosphere**: This is the solid outer part of the Earth, including the land and soil where organisms live.
3. **Atmosphere**: This is the layer of gases surrounding the Earth, which is essential for respiration and photosynthesis.
4. **Hydrosphere**: This includes all water bodies like oceans, rivers, lakes, and groundwater, which are crucial for life.

### Step 3: Interactions within the Biosphere
In the biosphere, living organisms interact with both biotic (living) and abiotic (non-living) factors. Biotic factors include other organisms, while abiotic factors include elements like sunlight, temperature, water, and minerals.

### Step 4: Conclusion
Thus, the biosphere is a complex, interconnected system that comprises living organisms, lithosphere, atmosphere, and hydrosphere.

### Final Answer
A biosphere is composed of living organisms, lithosphere (land), atmosphere (air), and hydrosphere (water).

---