Metacentric, submetacentric, telocentric and acrocentric chromosomes are classified on the basis of:-

Answer

**Step-by-Step Solution:**

1. **Understanding Chromosomes**: Chromosomes are structures within cells that contain DNA and proteins. They play a crucial role in cell division and genetic inheritance.

2. **Defining Centromere**: The centromere is a specific region of a chromosome where the two sister chromatids are joined together. It is also the attachment point for spindle fibers during cell division.

3. **Classification of Chromosomes**: Chromosomes can be classified based on the position of the centromere. The four types are:
- **Metacentric Chromosomes**: The centromere is located at the center of the chromosome, resulting in two arms of equal length.
- **Submetacentric Chromosomes**: The centromere is slightly off-center, leading to one arm being longer than the other.
- **Acrocentric Chromosomes**: The centromere is located closer to one end, resulting in one very long arm and one very short arm.
- **Telocentric Chromosomes**: The centromere is located at the very end of the chromosome, resulting in one arm only.

4. **Examples in Humans**:
- Metacentric: Human chromosomes 1 and 3.
- Submetacentric: Human chromosomes 4 to 12.
- Acrocentric: Human chromosomes 13, 15, 21, and 22.
- Telocentric: Humans do not possess telocentric chromosomes.

5. **Conclusion**: Therefore, metacentric, submetacentric, telocentric, and acrocentric chromosomes are classified based on the **position of the centromere**.

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