The chromosomal abnormalities examined by amniocentesis are

Options

A. Turner's syndrome
B. Klinefelter' syndrome
C. Down syndrome
D. all the above

Answer

### Step-by-Step Solution:

1. **Understand Amniocentesis**:
- Amniocentesis is a medical procedure used to obtain a sample of amniotic fluid, which contains fetal cells. This fluid is analyzed to check for genetic abnormalities in the developing fetus.

2. **Identify Chromosomal Abnormalities**:
- The primary purpose of amniocentesis is to detect chromosomal abnormalities. These abnormalities can lead to various genetic disorders and syndromes.

3. **Common Chromosomal Abnormalities Detected**:
- **Down Syndrome**: This is caused by an extra copy of chromosome 21 (trisomy 21).
- **Turner Syndrome**: This condition occurs in females when one of the X chromosomes is missing or partially missing (monosomy X).
- **Klinefelter Syndrome**: This syndrome occurs in males who have an extra X chromosome (XXY).

4. **Conclusion**:
- The chromosomal abnormalities that can be examined through amniocentesis include Down syndrome, Turner syndrome, and Klinefelter syndrome. Therefore, the correct answer is that all these abnormalities can be detected through this procedure.

### Final Answer:
The chromosomal abnormalities examined by amniocentesis include Down syndrome, Turner syndrome, and Klinefelter syndrome. The correct option is D: all the above.

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