Satellite chromosomes have

Options

A. Primary constriction only
B. Secondary constriction only
C. Tertiary constriction only
D. Both primary and secondary constriction

Answer

**Step-by-Step Solution:**

1. **Understanding Chromosome Structure**:
- Chromosomes have specific structures that include constrictions. The primary constriction is where the centromere is located, and it is crucial for the movement of chromosomes during cell division.

2. **Identifying Constrictions**:
- In addition to the primary constriction, some chromosomes have a secondary constriction. The area around the secondary constriction is referred to as the satellite region.

3. **Defining Satellite Chromosomes**:
- Satellite chromosomes are characterized by the presence of both primary and secondary constrictions. The primary constriction is essential for the chromosome's function during cell division, while the secondary constriction is associated with the satellite region.

4. **Evaluating Options**:
- The question asks what satellite chromosomes have. The options include:
- A) Only primary constrictor
- B) Only secondary constrictor
- C) Tertiary constrictor
- D) Both primary and secondary constrictors
- Based on the understanding of satellite chromosomes, we can conclude that they contain both primary and secondary constrictors.

5. **Final Answer**:
- Therefore, the correct answer is D) Both primary and secondary constrictors.

---