______sysrtems of classification were based on nature affinities among the organisms.

Options

A. Artificial
B. Natural
C. Phylogenetic
D. sexual

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a type of classification system that is based on the natural affinities among organisms.

2. **Identifying the Classification Systems**: There are various classification systems in biology, including artificial, natural, and phylogenetic systems. The question specifically refers to one that emphasizes natural relationships.

3. **Defining Natural System of Classification**: The natural system of classification is one that organizes organisms based on their natural relationships and similarities. This system considers various characteristics of organisms.

4. **Characteristics Considered in Natural Classification**:
- **Morphological Characters**: These are the physical traits of organisms, such as shape and structure.
- **Anatomical Characters**: These refer to the internal structures and systems of organisms.
- **Cytological Characters**: These involve the cellular structure and function.
- **Physiological Characters**: These relate to the functions and processes of the organisms.
- **Ontogeny**: This is the development of an organism from embryo to adult.
- **Reproductive Characters**: These include the methods and structures involved in reproduction.
- **Cytochemistry and Biochemistry**: These involve the chemical processes and substances within cells.

5. **Conclusion**: Based on the above characteristics and the emphasis on natural affinities, the answer to the question is the "Natural System of Classification".

**Final Answer**: Natural system of classification.

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