Which type of study begins with a group of people who already have a disease and then looks into factors that are associated with that disease?

What is involved in a C-section?

What will be an ideal response?

Carissa is 45 years old and is in her 5th week of pregnancy. She decides that she would like to find out as early as possible whether her unborn child has Down syndrome or any genetic abnormality. What test is she most likely to get?

a. Fetal monitoring b. Ultrasound c. Amniocentesis d. Chorionic villus sampling