Classification of organisms on the basis of natural affinities `:`

Options

A. Was given by Theophrastus
B. Does not consider embryology and phytochemistry
C. Becomes more important when there is no supporting fossil evidence
D. Is more practical and also used in arrangement of herbaria sheets.

Answer

### Step-by-Step Solution:

1. **Understanding Natural Affinities**:
- Natural affinities refer to the relationships and similarities between organisms based on their evolutionary history and characteristics. This classification system groups organisms based on how they interact with their environment and their biological traits.

2. **Identifying the Classification System**:
- The natural system of classification was primarily developed by the scientists Bentham and Hooker. They focused on grouping plants based on their natural relationships rather than arbitrary characteristics.

3. **Evaluating the Given Options**:
- **Option 1**: Therophrastus is mentioned. However, he did not establish the natural system of classification. This option is incorrect.
- **Option 2**: It claims that the natural system does not consider embryology and phytochemistry. This is incorrect because embryology (the study of embryos) and phytochemistry (the study of the chemical processes in plants) are crucial for understanding natural affinities.
- **Option 3**: This option states that the natural system is more important when there is no supporting fossil evidence. This is misleading because the classification is based on natural relationships and does not solely rely on fossil evidence.
- **Option 4**: This option claims that the natural system is practical and used in the arrangement of herbarium sheets. This is correct because the natural classification helps in organizing plant specimens for study.

4. **Conclusion**:
- After evaluating all options, the correct choice is the last option, which highlights the practicality of the natural classification system and its application in arranging herbarium sheets.

### Final Answer:
The classification of organisms on the basis of natural affinities is best represented by the system developed by Bentham and Hooker, which is practical and used in the arrangement of herbarium sheets.

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