Five kingdom system of classification is mainly based on

Options

A. Mode of nutrition
B. Complexity of body organisation
C. Ecological role
D. Complexity of cell structures

Answer

**Step-by-Step Solution:**

1. **Understanding the Five Kingdom System**: The Five Kingdom System of classification was proposed by R.H. Whittaker. It is a way to categorize living organisms based on certain criteria.

2. **Criteria for Classification**: Whittaker's classification is based on five main criteria:
- **Cell Structure**: This refers to whether the organism's cells are prokaryotic (without a nucleus) or eukaryotic (with a nucleus).
- **Thallus Organization**: This involves the complexity of the organism's body organization, whether unicellular or multicellular.
- **Mode of Nutrition**: This indicates how the organism obtains its food, whether through photosynthesis, absorption, or ingestion.
- **Reproductive Ability**: This refers to how organisms reproduce, whether sexually or asexually.
- **Phylogenetic Relationships**: This looks at the evolutionary relationships between different organisms.

3. **Identifying the Main Basis**: Among the criteria, the most significant basis for the classification into five kingdoms is the **complexity of cell structure**. This is because it fundamentally distinguishes between prokaryotic and eukaryotic organisms.

4. **Conclusion**: Therefore, the Five Kingdom System of classification is mainly based on the complexity of cell structure.

**Final Answer**: The Five Kingdom System of classification is mainly based on the complexity of cell structure.

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