The chief characteristic of class Ascomycetes is :-

Options

A. Formation of spores
B. Hyphae
C. Formation of ascospores
D. Formation of zoospores

Answer

### Step-by-Step Solution:

1. **Identify the Class**: The question asks about the chief characteristic of the class Ascomycetes, which is commonly known as sac fungi.

2. **Understand the Structure**: Ascomycetes are characterized by having septate hyphae. This means that their mycelium is branched and has cross walls (septa) that divide the hyphae into individual cells.

3. **Spores Formation**: In Ascomycetes, spores are formed within a specialized structure called an ascus. These spores are known as ascospores. This is a defining feature of Ascomycetes.

4. **Comparison with Other Classes**:
- Phycomycetes produce asexual spores called zoospores.
- Basidiomycetes do not have asexual spores.
- Deuteromycetes produce asexual spores known as conidia.
- The presence of ascospores is unique to Ascomycetes.

5. **Conclusion**: The chief characteristic of Ascomycetes is the formation of ascospores within an ascus, which is a defining feature that distinguishes them from other fungal classes.

### Final Answer:
The chief characteristic of class Ascomycetes is the formation of ascospores within an ascus.

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