Lichen is pioneer in succession

Options

A. Hydrosphere
B. Lithosphere
C. Psammosere
D. Xerosere

Explanation

### Step-by-Step Solution:

1. **Understanding Lichens**: Lichens are a symbiotic association between algae and fungi. This unique partnership allows them to thrive in harsh environments, making them important pioneers in ecological succession.

2. **Definition of Pioneer Species**: Pioneer species are the first organisms to colonize barren or disturbed environments. They play a crucial role in soil formation and creating conditions suitable for other species to thrive.

3. **Role of Lichens in Succession**: Lichens can grow on bare rocks and surfaces where few other organisms can survive. They contribute to the weathering of rocks, breaking them down into soil, which is essential for subsequent plant growth.

4. **Evaluating the Options**:
- **Hydrosphere**: This refers to all the water bodies on Earth. Lichens do not grow in water, so this option is incorrect.
- **Lithosphere**: This is the solid outer part of the Earth, including the crust and upper mantle. Lichens grow on rocks and soil, making this option correct.
- **Samosphere**: This term seems to be a misinterpretation; it does not refer to a recognized ecological term. Therefore, it is incorrect.
- **Other Options**: Any other options related to water or unsuitable environments would also be incorrect.

5. **Conclusion**: Based on the analysis, Lichens are indeed pioneers in succession, particularly in the lithosphere, where they help initiate the process of soil formation and ecosystem development.

### Final Answer:
Lichens are pioneers in succession, specifically in the lithosphere.

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