- A PCR alone, performed directly on collected maternal blood plasma samples
- B Amniocentesis and chorionic villus sampling (CVS) -- fetal cells analyzed
- C ELISA alone, detecting maternal antibody levels in blood serum
- D Gel electrophoresis alone, run directly on maternal serum samples
Correct answer: B. Amniocentesis and chorionic villus sampling (CVS) -- fetal cells analyzed
Explanation: Amniocentesis (14-20 weeks): fetal cells from amniotic fluid analyzed. CVS (10-12 weeks): placental cells biopsied. Both allow chromosomal and genetic analysis.
Concept context
Recombinant DNA, GMOs, PCR, CRISPR, and biotechnology applications. Growing importance in NEET.
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