The classification of organisms on basis of number and size of chromosomes is called as

Options

A. Biochemical taxonomy
B. Numerical taxonomy
C. Chemo taxonomy
D. Karyotaxonomy

Answer

To solve the question regarding the classification of organisms based on the number and size of chromosomes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the specific term used to classify organisms based on their chromosomes' number and size.

2. **Identify the Options**: The options provided are:
- A) Biochemical taxonomy
- B) Numerical taxonomy
- C) Chemo taxonomy
- D) Karyotaxonomy

3. **Analyze Each Option**:
- **Biochemical Taxonomy**: This method classifies organisms based on similarities in the structure of certain biochemical compounds. It does not focus on chromosomes.
- **Numerical Taxonomy**: This classification is based on observable characteristics of organisms, not specifically on chromosomes.
- **Chemo Taxonomy**: This approach uses the chemical constituents of organisms for classification, which again does not involve chromosome analysis.
- **Karyotaxonomy**: This term specifically refers to the classification of organisms based on the number and structure of their chromosomes.

4. **Select the Correct Answer**: Based on the analysis, the correct answer is **Karyotaxonomy** (Option D), as it directly relates to the classification based on chromosomes.

### Final Answer:
The classification of organisms on the basis of number and size of chromosomes is called **Karyotaxonomy**.