The 32-cells stage of the human embryo is

Options

A. Smaller than the fertilized egg
B. Of the same size as the fertilized egg
C. Two times the size of the fertilized egg
D. Four times the size of the fertilized egg

Answer

To answer the question regarding the size of the 32-cell stage of the human embryo, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Stages of Embryonic Development**: The development of a human embryo begins with a fertilized egg, known as a zygote. This zygote undergoes a series of mitotic divisions, leading to the formation of a multicellular structure.

2. **Identifying the 32-Cell Stage**: The 32-cell stage of the embryo is known as the blastula. Prior to this stage, the embryo goes through several divisions, starting from the zygote to the 2-cell stage, then to the 4-cell stage, the 8-cell stage, and finally to the 16-cell stage (morula) before reaching the 32-cell stage.

3. **Cell Division Process**: The process of cell division that occurs during these stages is called cleavage. Cleavage involves rapid mitotic divisions without significant growth in cell size, meaning that the total size of the embryo does not increase proportionally with the number of cells.

4. **Comparing Sizes**: At the 32-cell stage (blastula), the individual cells are approximately the same size as the original fertilized egg (zygote). This is because the cells do not grow larger during the cleavage process; they simply divide.

5. **Conclusion**: Therefore, the correct answer to the question is that the 32-cell stage of the human embryo is of the same size as the fertilized egg.

### Final Answer:
The 32-cells stage of the human embryo is of the same size as the fertilized egg.

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