Lichens are ecologically important as they

Options

A. Purify air
B. Are pioneers on barren rocks
C. Are symbionts of algae and fungi
D. Are associated with mycorrhizal roots

Answer

### Step-by-Step Solution:

1. **Understanding Lichens**: Lichens are a unique biological entity formed by the symbiotic association of two different organisms: algae and fungi. This relationship is known as mutualism, where both organisms benefit from each other.

2. **Role of Algae**: In this symbiotic relationship, the algal component of the lichen is responsible for photosynthesis. Through this process, algae produce food (glucose) using sunlight, which serves as a primary energy source for both the algae and the fungi.

3. **Role of Fungi**: The fungal component provides structure, protection, and moisture retention to the lichen. It helps anchor the lichen to various surfaces, such as rocks or trees, and offers a suitable environment for the algae to thrive.

4. **Pioneer Species**: Lichens are often referred to as pioneer species. This means they are among the first organisms to colonize barren environments, such as bare rocks or areas where soil is not yet established. They play a crucial role in ecological succession by preparing the environment for other organisms.

5. **Ecological Importance**: By breaking down rock surfaces and contributing to soil formation, lichens facilitate the establishment of other plant species. This process is essential for the development of ecosystems, as it allows for greater biodiversity over time.

6. **Conclusion**: Therefore, lichens are ecologically important because they serve as pioneer species in barren environments, contribute to soil formation, and support the establishment of more complex ecosystems.