Component of a chromosome which divides it into two arms is

Options

A. Primary constriction
B. Secondary constriction
C. Nuclear organizer
D. Trebent

Answer

To answer the question, "Component of a chromosome which divides it into two arms is," we need to identify the correct term that refers to the structure responsible for this division.

### Step-by-Step Solution:

1. **Understanding Chromosome Structure**:
- A chromosome consists of two main parts known as arms. These arms are typically referred to as the short arm (p arm) and the long arm (q arm).

2. **Identifying Key Components**:
- The question provides several options: primary constriction, secondary constriction, nuclear organizer, and prevent. We need to analyze each option to determine which one divides the chromosome into two arms.

3. **Analyzing the Options**:
- **Nuclear Organizer**: This refers to the nuclear organizing region (NOR), which is involved in the formation of ribosomal RNA but does not divide the chromosome into arms. Therefore, this option is incorrect.
- **Secondary Constriction**: This is often associated with the NOR and does not serve the purpose of dividing the chromosome into two arms. Hence, this option is also incorrect.
- **Telomere**: Telomeres are the ends of the chromosomes and do not divide the chromosome into arms. This option is incorrect as well.
- **Primary Constriction**: This is also known as the centromere. The centromere is the region of the chromosome that divides it into the two arms (p and q). This is the correct answer.

4. **Conclusion**:
- The component of a chromosome that divides it into two arms is the **primary constriction**, which is also referred to as the **centromere**.

### Final Answer:
The component of a chromosome which divides it into two arms is the **primary constriction (centromere)**.

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