During cleavage all of the following increase , except

Options

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

Answer

To solve the question, "During cleavage, all of the following increase, except:", we need to analyze the processes that occur during cleavage in embryonic development.

### Step-by-Step Solution:

1. **Understanding Cleavage**: Cleavage is the series of rapid mitotic divisions that occur after fertilization, leading to the formation of a multicellular embryo from a single zygote.

2. **Increase in Number of Cells**: During cleavage, the zygote divides to form multiple cells called blastomeres. The number of cells increases exponentially (2, 4, 8, 16, etc.).

3. **Nuclear-Cytoplasmic Ratio**: As the number of cells increases, the nuclear-cytoplasmic ratio also increases. This is because each new cell has a nucleus, and the cytoplasm is divided among the increasing number of cells.

4. **Size of Blastomere**: Although the number of blastomeres increases, the size of each individual blastomere does not increase during cleavage. Instead, as the cells divide, they become smaller.

5. **Metabolism**: With the increase in the number of cells, the overall metabolic activity of the embryo also increases. More cells mean more metabolic processes occurring simultaneously.

6. **Conclusion**: Among the options given (number of cells, nuclear-cytoplasmic ratio, size of blastomere, and metabolism), the only factor that does not increase during cleavage is the size of the blastomere.

### Final Answer:
The correct answer is **size of blastomere**.

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