Which of the following characteristics does not belong to cleavage

Options

A. Decrease in size of blastomeres
B. Rapid mitotic cell division
C. Interphase of very short duration
D. Differention of blastomeres

Answer

To determine which characteristic does not belong to cleavage, we need to analyze each option in the context of what cleavage entails.

### Step-by-Step Solution:

1. **Understanding Cleavage**: Cleavage is the series of rapid mitotic divisions that a zygote undergoes after fertilization. This process occurs before the zygote implants into the uterine wall and does not involve an increase in the overall size of the zygote.

2. **Analyzing the Options**:
- **Option A: Decrease in size of blastomeres**: During cleavage, the zygote divides into smaller cells called blastomeres. While the overall size of the zygote does not change, the individual blastomeres do decrease in size. Therefore, this characteristic belongs to cleavage.

- **Option B: Rapid mitotic cell division**: Cleavage is characterized by rapid mitotic divisions. This is a defining feature of the cleavage process. Thus, this characteristic belongs to cleavage.

- **Option C: Interphase of very short duration**: In cleavage, the interphase (the phase of the cell cycle where the cell is not dividing) is indeed very short compared to other cell cycles. This characteristic is also a part of cleavage.

- **Option D: Differentiation of the blastomeres**: Differentiation refers to the process where cells become specialized in structure and function. This process occurs after cleavage, during the formation of the gastrula, not during cleavage itself. Therefore, this characteristic does not belong to cleavage.

3. **Conclusion**: The characteristic that does not belong to cleavage is **Option D: Differentiation of the blastomeres**.

### Final Answer:
**Option D: Differentiation of the blastomeres** does not belong to cleavage.