At what stage in test-tube baby technique, the embryo is implanted in human female?

Options

A. 32-celled stage
B. 64-celled stage
C. 100 -celled stage
D. 164-celled stage

Answer

To answer the question about the stage at which the embryo is implanted in the test-tube baby technique, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Test-Tube Baby Technique**: The test-tube baby technique, also known as in vitro fertilization (IVF), involves fertilizing an egg with sperm outside the human body and then transferring the resulting embryo into the uterus of a female.

2. **Identify the Development Stages of the Embryo**: After fertilization, the embryo undergoes several stages of cell division:
- The first division occurs, leading to a 2-cell stage.
- This continues to the 4-cell stage, then the 8-cell stage, and so on.
- Eventually, the embryo reaches the 32-cell stage, which is known as the blastomere stage.

3. **Determine the Correct Stage for Implantation**:
- The embryo is typically implanted in the uterus at the 32-cell stage (blastomere stage). This is the stage where the embryo is still in the early developmental phase and can successfully implant in the uterine lining.
- Other stages such as the 64-cell stage (morula), 100-cell stage, and 164-cell stage are more advanced stages of development and are not the typical points for implantation.

4. **Conclude the Answer**: Therefore, the correct answer to the question is that the embryo is implanted in the human female at the **32-cell stage**.

### Final Answer:
The embryo is implanted in the human female at the **32-cell stage**.

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