The least level of chromosome organization is

Options

A. solenoid
B. 30 nm fibre
C. nucleosome
D. none of these

Answer

To determine the least level of chromosome organization, we can break down the process step by step:

### Step 1: Understanding Chromosome Structure
- Chromosomes are thread-like structures located in the nucleus of both plant and animal cells. They are made up of DNA and proteins, primarily histones.

### Step 2: Identifying the Basic Unit
- The basic functional unit of heredity is the gene, which is composed of DNA. The DNA itself is made up of nucleotides.

### Step 3: Formation of Nucleosomes
- The negatively charged DNA wraps around positively charged histone proteins to form a structure known as a nucleosome. This is the first level of organization in the chromosome structure.

### Step 4: Higher Levels of Organization
- After nucleosomes, the next level of organization is the formation of the 30 nm fiber (also known as the solenoid structure), which is a higher-order structure formed by the coiling of nucleosomes.

### Conclusion
- Therefore, the least level of chromosome organization is the **nucleosome**.

### Final Answer
The least level of chromosome organization is **nucleosome**.

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