During cleavage, nucleocytoplasmic ratio nucelus/cytoplasm

Options

A. Increases
B. Decreases
C. Remains same
D. None of the above.

Answer

### Step-by-Step Solution:

1. **Understanding Cleavage**:
- Cleavage is the series of rapid cell divisions that occur after fertilization. This process leads to the formation of a cluster of cells called a blastula, which retains the overall size of the original zygote.

**Hint**: Remember that cleavage occurs after fertilization and involves rapid cell divisions.

2. **Types of Cleavage**:
- There are two types of cleavage: holoblastic (complete division) and meroblastic (partial division). Both types lead to an increase in cell number.

**Hint**: Know the difference between holoblastic and meroblastic cleavage.

3. **Nuclear and Cytoplasmic Mass**:
- During cleavage, while the number of cells and nuclear mass increases, the total amount of cytoplasm remains constant. This is because the cytoplasm is divided among the newly formed cells.

**Hint**: Focus on how the cytoplasm is distributed among daughter cells during cleavage.

4. **Nucleocytoplasmic Ratio**:
- As the number of nuclei increases and the cytoplasmic mass remains the same, the ratio of nucleus to cytoplasm (nucleocytoplasmic ratio) increases. This means that there is more nuclear material relative to the amount of cytoplasm.

**Hint**: Consider how the increase in nuclei affects the ratio compared to the unchanged cytoplasmic mass.

5. **Conclusion**:
- Therefore, during cleavage, the nucleocytoplasmic ratio increases.

**Final Answer**: The correct option is **(1) increases**.