Lichens and mosses are observed in

Options

A. Hydrosere
B. Xerosere
C. Hydrarch succession
D. Psammosere

Answer

### Step-by-Step Solution:

1. **Understanding Lichens and Mosses**:
- Lichens are symbiotic organisms made up of fungi and algae. They are known for their ability to survive in harsh environments.
- Mosses are simple, non-vascular plants that thrive in moist environments but can also tolerate some dryness.

2. **Identifying Ecosystems**:
- The question asks in which ecosystem lichens and mosses are typically found. We need to analyze the options provided.

3. **Analyzing the Options**:
- **Hydroser**: This ecosystem is characterized by plant succession in water environments. Since lichens and mosses are not primarily aquatic, this option is not suitable.
- **Xeroser**: This ecosystem has limited water availability, making it suitable for organisms like lichens and mosses, which can tolerate dry conditions.
- **Hydrarch Succession**: This refers to plant succession that starts in water and progresses to a forest. Again, this is not where lichens and mosses are predominantly found.
- **Samoseer**: This is a seral ecosystem where new plants grow in newly formed coastal sand. This is not the typical habitat for lichens and mosses.

4. **Conclusion**:
- After analyzing all options, the most suitable ecosystem where lichens and mosses are observed is **Xeroser**.

### Final Answer:
- The correct answer is **Option B: Xeroser**.