Lichens represent mutualism between

Options

A. Fungus and higher plants
B. Fungus and cyanobacteria
C. Sea anemone and clown fish
D. Barnacle and whale

Answer

**Step-by-Step Solution:**

1. **Understanding Lichens**: Lichens are complex organisms that consist of two or more different organisms living together in a close relationship. They are primarily composed of a fungus and a photosynthetic partner.

2. **Identifying the Partners**: The two main partners in a lichen are:
- **Fungus**: This is the main structural component of the lichen. It provides the overall shape and structure, known as the thallus.
- **Photobiont**: This can either be an alga or a cyanobacterium. These organisms are capable of photosynthesis.

3. **Function of Each Partner**:
- The **fungus** is heterotrophic, meaning it cannot produce its own food and relies on external sources. It benefits from the relationship by receiving carbohydrates produced by the photobiont through photosynthesis.
- The **photobiont** (alga or cyanobacterium) performs photosynthesis, converting light energy into chemical energy, and produces simple sugars that serve as food for the fungus.

4. **Mutual Benefits**:
- The **fungus** provides a protective structure for the photobiont, helping it retain moisture and providing a suitable environment for growth.
- The **photobiont** supplies the fungus with carbohydrates, which are essential for its survival.

5. **Conclusion**: Therefore, lichens represent a mutualistic relationship between a fungus and a photobiont (which can be either algae or cyanobacteria). This relationship is beneficial to both organisms involved.

**Final Answer**: Lichens represent mutualism between a fungus and a photobiont (algae or cyanobacteria).

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