Dinomitosis is characterised by

Options

A. Intranuclear spindle
B. Absence of spindle
C. Absence of chromosome movement
D. All the above

Answer

### Step-by-Step Solution:

1. **Understanding Dinomitosis**:
- Dinomitosis is a type of cell division observed specifically in dinoflagellates, which are a group of protists.

2. **Characteristics of Dinomitosis**:
- Unlike typical mitosis, where the nuclear membrane disappears, in dinomitosis, the nuclear membrane remains intact throughout the process.

3. **Spindle Formation**:
- In dinomitosis, spindle fibers form within the nucleus, which is referred to as an "intranuclear spindle." This is a unique feature of dinomitosis.

4. **Chromosome Movement**:
- During dinomitosis, chromosomes do move, but they do so within the confines of the nuclear membrane. This movement is similar to that in standard mitosis.

5. **Evaluating the Options**:
- **Optional intranuclear spindle**: This is incorrect; the intranuclear spindle is a defining characteristic of dinomitosis.
- **Absence of spindle**: This is also incorrect; spindle formation does occur within the nucleus.
- **Absence of chromosome movement**: This is incorrect; chromosomes do move during dinomitosis.
- **All of the above**: Since the previous statements are incorrect, this option is also incorrect.

6. **Conclusion**:
- The correct characteristic of dinomitosis is the presence of an intranuclear spindle, making option A the correct answer.

### Final Answer:
Dinomitosis is characterized by the presence of an intranuclear spindle.

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