The basis of modern taxonomic studies are :-
(a) External and internal structure
(b) Structure of cell
(c) Development process
(d) Ecological informations

Options

A. a and b
B. a, b and c
C. a, c and d
D. All a, b, c and d

Answer

To solve the question regarding the basis of modern taxonomic studies, we need to analyze each option provided:

1. **Understanding Taxonomy**: Taxonomy is the science of classification, which includes the identification, naming, and classification of organisms. It relies on various biological disciplines to categorize living organisms.

2. **Analyzing the Options**:
- **(a) External and internal structure**: This refers to morphology, which is crucial for identifying and classifying organisms based on their physical characteristics.
- **(b) Structure of cell**: This involves cytology, which is important for understanding the cellular organization and differences among organisms.
- **(c) Development process**: This refers to embryology, which studies the development of organisms from fertilization to maturity, providing insights into evolutionary relationships.
- **(d) Ecological information**: This includes the study of organisms' interactions with their environment, which is essential for understanding their roles in ecosystems and their evolutionary adaptations.

3. **Conclusion**: All the options (a, b, c, and d) contribute significantly to modern taxonomic studies. Therefore, the correct answer is that all these aspects are fundamental to taxonomy.

**Final Answer**: The basis of modern taxonomic studies are (a) External and internal structure, (b) Structure of cell, (c) Development process, and (d) Ecological information. Thus, the correct option is **all A, B, C, and D**.

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