Yeasts are an exception in kingdom Fungi because they are unicellular.

Answer

### Step-by-Step Solution:

1. **Understanding Yeasts in Kingdom Fungi**:
- Yeasts are classified under the kingdom Fungi, which is primarily known for its multicellular and filamentous organisms, such as molds and mushrooms.
- However, yeasts are unicellular organisms, which makes them an exception within this kingdom.

2. **Characteristics of Fungi**:
- Fungi are characterized by their absorptive mode of nutrition, meaning they absorb nutrients from their environment.
- They typically reproduce via spore formation, which is a common reproductive strategy among fungi.

3. **Comparison with Protozoans**:
- Protozoans, in contrast to fungi, have a holozoic mode of nutrition, meaning they ingest food and digest it internally.
- Protozoans also reproduce differently, often through binary fission or other means, rather than spore formation.

4. **Reproductive Mechanism of Yeasts**:
- Yeasts primarily reproduce through a process called budding, which is different from the spore formation seen in many other fungi.
- Despite their unicellular nature, yeasts share other fundamental characteristics with fungi, such as the absorptive mode of nutrition.

5. **Conclusion**:
- While yeasts are indeed an exception in the kingdom Fungi due to their unicellular structure, they still possess the key characteristics that classify them as fungi rather than protozoans.