Members of which fungal class are found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites.

Answer

**Step-by-Step Text Solution:**

1. **Identify the Fungal Class**: The question asks for the fungal class that includes members found in aquatic habitats, on decaying wood, and as obligate parasites. The correct answer is the class **Phycomycetes**.

2. **Habitat and Characteristics**: Members of the Phycomycetes are typically found in moist and damp environments, including aquatic habitats. They thrive on decaying organic matter such as wood.

3. **Examples of Phycomycetes**:
- **Rhizopus**: Commonly known as bread mould, it is often found on bread in moist conditions.
- **Albugo**: This is a parasitic fungus that affects plants, specifically known to be a parasite on mustard plants.
- **Mucor**: Another example of fungi belonging to this class.

4. **Morphological Features**:
- The mycelium of Phycomycetes is **aseptate** (lacking septa) and **cenocytic** (multinucleate).
- Asexual reproduction occurs through the formation of **zoospores**, which are motile, or **aplanospores**, which are non-motile.
- In sexual reproduction, spores are produced **endogenously** within a structure called the **sporangium**.

5. **Conclusion**: Therefore, the members of the fungal class Phycomycetes are found in aquatic habitats, on decaying wood, and can act as obligate parasites.

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