Whittaker's classification is based on
(a) Cell structure
(b) Body structure
(c) Nutrition
(d) All the above

Options

A. Cell structure
B. Body structure
C. Nutrition
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Understanding Whittaker's Classification**: R.H. Whittaker proposed a classification system known as the five kingdom classification in 1969. This system categorizes living organisms into five distinct kingdoms: Monera, Protista, Fungi, Plantae, and Animalia.

2. **Key Criteria for Classification**: Whittaker's classification is based on several key characteristics of organisms:
- **Cell Structure**: This refers to whether organisms are prokaryotic (lacking a nucleus) or eukaryotic (having a nucleus).
- **Body Structure**: This includes the overall organization of the organism, such as thallus organization in plants and body structure in animals.
- **Nutrition**: The mode of nutrition (autotrophic or heterotrophic) is a significant factor in distinguishing between different kingdoms.

3. **Analyzing the Options**:
- **Option (a) Cell Structure**: Correct, as it is one of the bases for classification.
- **Option (b) Body Structure**: Correct, as it is also a criterion used in the classification.
- **Option (c) Nutrition**: Correct, as the mode of nutrition is fundamental to the classification.
- **Option (d) All of the above**: Since options (a), (b), and (c) are all correct, this option is also correct.

4. **Conclusion**: Since all the options (a), (b), and (c) are included in Whittaker's classification criteria, the correct answer is (d) All of the above.

**Final Answer**: (d) All the above

---