What are the essential basis of modern taxonomic studies?

Options

A. Ecological information of organisms
B. Development process
C. External and internal structure
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Taxonomy**: Taxonomy is a branch of biology that deals with the identification, classification, and naming of organisms. It involves principles and procedures that help in organizing biological diversity.

2. **Modern Taxonomic Studies**: Unlike classical taxonomy, which primarily focused on external and internal structures, modern taxonomy incorporates a variety of criteria for classification.

3. **Essential Bases of Modern Taxonomic Studies**:
- **Morphology**: This involves the study of the external structure and forms of organisms. Morphological characteristics help in identifying and classifying organisms.
- **Cytology**: This is the study of the internal structure of cells. Understanding cellular organization and function is crucial for classification.
- **Embryology**: This involves the study of developmental processes of organisms. It helps in understanding how organisms develop from embryos to their adult forms.
- **Ecological Relationships**: This includes studying the habitats of organisms and their interactions with the environment. It provides insight into how organisms adapt to their surroundings.
- **Genetics**: The study of genes and heredity is essential for understanding the evolutionary relationships between organisms.
- **Biochemistry**: This involves studying the metabolic pathways and physiological processes of organisms, which can reveal important information about their classification.

4. **Conclusion**: All of the above criteria—morphology, cytology, embryology, ecological relationships, genetics, and biochemistry—are essential bases for modern taxonomic studies. Therefore, the correct answer is "all of these."