During cleavage all of the following increase , except

Options

A. Number of cells
B. Nuclear cytoplasmic ratio
C. Size of blastomere
D. Metabolism

Answer

**Step-by-Step Solution:**

1. **Understanding Cleavage**: Cleavage is the process that occurs after fertilization, where the zygote undergoes a series of rapid mitotic divisions. This leads to the formation of smaller cells called blastomeres.

2. **Characteristics of Cleavage**: During cleavage, the following characteristics are observed:
- The number of cells increases as the zygote divides.
- The nuclear-cytoplasmic ratio increases because the nucleus divides while the overall cytoplasmic volume does not increase proportionally.
- The size of the blastomeres decreases with each division, as the cells become smaller but more numerous.

3. **Identifying the Exception**: The question asks which of the following does NOT increase during cleavage.
- The number of cells increases.
- The nuclear-cytoplasmic ratio increases.
- The size of the blastomeres decreases.

4. **Conclusion**: Since the size of the blastomeres decreases during cleavage, this is the exception to the other parameters that increase. Therefore, the correct answer is that the size of the blastomeres does not increase during cleavage.

**Final Answer**: The size of the blastomeres does not increase during cleavage.

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