In embryo,cleavage brings about

Options

A. Increased size
B. increased DNA content
C. change in shape and size
D. increased mass of protoplasm

Answer

### Step-by-Step Solution:

1. **Understanding Cleavage**: Cleavage is the series of rapid cell divisions that occur after fertilization. It transforms the single-celled zygote into a multicellular structure.

2. **Formation of Zygote**: The process begins with the fusion of a male gamete (sperm) and a female gamete (ovum) to form a zygote.

3. **Cell Division**: After the zygote is formed, it undergoes cleavage, which involves repeated mitotic divisions. Initially, the zygote divides into two cells, then four, and continues to divide until it reaches a stage called the morula, which typically has around 16 cells.

4. **Development of Blastula**: The morula continues to divide and eventually forms a blastula, which can consist of approximately 32 cells.

5. **Cell Size and DNA Content**: Throughout this process, the overall size of the embryo does not increase significantly. Instead, the number of cells increases while the size of each individual cell remains relatively constant.

6. **Change in Nucleus Count**: As the cleavage progresses, the number of nuclei increases because each new cell formed during cleavage contains its own nucleus.

7. **Conclusion**: The key outcome of cleavage is the increase in DNA content due to the formation of multiple nuclei without a corresponding increase in cell size or mass of protoplasm. Therefore, cleavage primarily leads to an increase in the number of cells and their DNA content.

### Final Answer:
In embryo, cleavage brings about increased DNA content.