Question: Which of the following best describes the maternal serum quad screen? Group of answer choices serologic screening testing to detect risk for neural tube defects, and trisomies 18 and 21 serologic screening testing to detect risk for neural tube defects, and trisomies 13 and 21 a prenatal test on tissue obtained from the placenta that diagnoses chromosomal abnormalities diagnostic medical imaging used to visualize a fetus