Select first group of organisms to colonise rocks and hence, are of great ecological importance.

Options

A. Mosses alonwith horsetials
B. Mosses alongwith lichens
C. Ferns alongwith mosses
D. Mosses alongwith grasses

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the first group of organisms that colonize rocks and have significant ecological importance. This involves recognizing the role of these organisms in ecological succession.

2. **Identifying the Options**: The options provided are:
- (A) Mosses along with horsetails
- (B) Mosses along with lichens
- (C) Ferns along with mosses
- (D) Mosses along with grasses

3. **Analyzing the Options**:
- **Mosses and Horsetails**: While mosses are important, horsetails are not typically the first colonizers.
- **Mosses and Lichens**: Lichens are known to be pioneer species that can survive in harsh conditions and help in the weathering of rocks.
- **Ferns and Mosses**: Ferns are more advanced plants that usually come after mosses and lichens in succession.
- **Mosses and Grasses**: Grasses are not the first colonizers; they appear later in the succession process.

4. **Conclusion**: Based on the analysis, the correct answer is (B) Mosses along with lichens. These organisms are crucial for soil formation and are the first to colonize bare rocks.

5. **Ecological Importance**: Mosses and lichens contribute to the ecosystem by breaking down rocks, forming soil, and providing habitat for other organisms.

**Final Answer**: The first group of organisms to colonize rocks and are of great ecological importance is **Mosses along with Lichens**.

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