Cleavage start in human zygote at

Options

A. Fallopian tube
B. Uterus
C. Vagina
D. None

Answer

**Step-by-Step Solution:**

1. **Understanding Cleavage**: Cleavage is the process of mitotic division that occurs after fertilization, resulting in the formation of multiple cells from a single zygote.

2. **Location of Fertilization**: In humans, fertilization occurs in the fallopian tube. This is where the sperm meets the egg, leading to the formation of the zygote.

3. **Movement of the Zygote**: After fertilization, the zygote begins to move through the isthmus of the fallopian tube towards the uterus.

4. **Initiation of Cleavage**: Cleavage begins as the zygote travels through the isthmus. This is the point where the zygote starts dividing into smaller cells known as blastomeres.

5. **Formation of Blastomeres**: As cleavage continues, the zygote divides into 2, then 4, then 8, and so on, resulting in a cluster of cells called blastomeres.

6. **Development of Morula and Blastocyst**: The blastomeres continue to divide and form a solid ball of cells known as the morula. Eventually, the morula develops into a blastocyst, which is the structure that will implant into the uterus.

7. **Conclusion**: Therefore, the cleavage in the human zygote starts in the fallopian tube, specifically in the isthmus region.

**Final Answer**: Cleavage starts in the human zygote at the **fallopian tube**.

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