Which of the following techniques cannot be used to determine the genetic defect of an embryo?

Options

A. Ultrasound
B. CVS
C. PUBS
D. Amniocentesis

Answer

To determine which technique cannot be used to identify genetic defects in an embryo, we will analyze the provided options one by one.

### Step 1: Identify the Techniques
The techniques mentioned in the question are:
1. Ultrasound
2. Chorionic Villus Sampling (CVS)
3. Percutaneous Umbilical Blood Sampling (PUBS)
4. Amniocentesis

### Step 2: Analyze Each Technique
- **Ultrasound**: This technique uses sound waves to create images of the embryo. It can show the physical structure and movement of the embryo but does not provide information about genetic defects. Thus, it cannot be used to determine genetic defects.

- **Chorionic Villus Sampling (CVS)**: This is a prenatal diagnostic test where a sample of chorionic villi is taken from the placenta. It can detect genetic defects and chromosomal abnormalities in the embryo.

- **Percutaneous Umbilical Blood Sampling (PUBS)**: This technique involves taking a sample of the fetal blood from the umbilical cord. It can be used to diagnose genetic conditions and other blood disorders.

- **Amniocentesis**: This procedure involves extracting amniotic fluid surrounding the embryo. The fluid contains fetal cells that can be tested for genetic defects and chromosomal abnormalities.

### Step 3: Conclusion
Based on the analysis, the technique that cannot be used to determine genetic defects in an embryo is **Ultrasound**.

### Final Answer
**Ultrasound** is the technique that cannot be used to determine the genetic defect of an embryo.

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