Which kingdom of Whittaker's classification seems to be unnatural?

Options

A. Monera
B. Protista
C. Fungi
D. Animalia.

Answer

### Step-by-Step Solution:

1. **Understanding Whittaker's Classification**: Whittaker proposed a five-kingdom system that includes Monera, Protista, Fungi, Plantae, and Animalia. Each kingdom is based on distinct characteristics of organisms.

2. **Analyzing the Kingdoms**:
- **Monera**: This kingdom consists of prokaryotic organisms, which are unicellular and lack a nucleus. They exhibit natural classification based on their cellular structure and modes of nutrition (heterotrophic and absorptive).
- **Protista**: This kingdom includes unicellular eukaryotic organisms. An example is Euglena, which can perform photosynthesis (autotrophic) but is classified as a protist. This duality in characteristics (plant-like and animal-like) indicates an unnatural classification.
- **Fungi**: This kingdom consists of organisms that are primarily multicellular (with some unicellular forms like yeast) and have a distinct mode of heterotrophic nutrition through absorption. Their classification is consistent and natural.
- **Animalia**: This kingdom includes multicellular organisms with a cell membrane. All members share common characteristics, making their classification natural.

3. **Identifying the Unnatural Kingdom**: Based on the analysis, the kingdom that appears unnatural is **Protista**. This is due to the presence of organisms like Euglena, which exhibit both plant and animal characteristics, leading to ambiguity in classification.

4. **Conclusion**: The kingdom that seems to be unnatural in Whittaker's classification is **Protista**.