Blastocyst stage can be located in

Options

A. Ampulla
B. Isthmus
C. Infundibulum
D. Uterus

Answer

### Step-by-Step Solution:

1. **Understanding the Blastocyst Stage**: The blastocyst is a developmental stage that occurs after fertilization. It typically forms around 5 days after fertilization when the fertilized egg (zygote) undergoes several divisions.

2. **Fertilization Location**: Fertilization occurs in the female reproductive system, specifically in the fallopian tubes. The fertilized egg then begins to divide and develop.

3. **Developmental Stages**: After fertilization, the zygote divides to form a 2-cell stage, then a 4-cell stage, and subsequently a morula stage, which is a solid ball of cells. After about 5 days, the morula develops into a blastocyst.

4. **Movement of the Blastocyst**: Once the blastocyst is formed, it moves from the fallopian tube into the uterus. This movement is crucial as the uterus is where implantation occurs.

5. **Implantation**: The blastocyst then attaches to the uterine lining in a process called implantation. This is essential for the continuation of pregnancy.

6. **Conclusion**: Therefore, the correct location for the blastocyst stage is the uterus, as this is where it implants after its formation.

### Final Answer:
The blastocyst stage can be located in the **uterus**.

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