Dr Smartz has been intensely engaged in a study of the twins Annete and Brad for the last two years. You would most accurately say that Dr Smartz is engaged in a,an

Question

A gender experiment
B correlational study
C cross-lagged method
D case study
I believe the correct answer is C

Marshall has been diagnosed with Down syndrome. You realize that Marshall's condition is related to
A alcohol abuse by the father
B abnormalities of the 21st pair of chromosomes.
C sex linked chromosomal abnormalities
D genetic errors in the 24st pair of chromosomes.
I believe the correct answer is B

Answer 1

I agree with both of your answers.

Answer 2

C is possibly the first answer, it would depend on that the Dr is studying. Lagged cross-coorelation coefficents look for delayed reactions in one twin due to a change in the other. Two years is a hint, but not conclusive.

B is correct on the second.

Answer 3

D is definitely the correct answer for the first question. The case study method follows individuals for a prolonged period of time — a longitudinal study. Two years would qualify as a long period of time.

You are right with the second question. Down syndrome is caused by a trisomy (an extra chromosome) of chromosome 21.

I hope this helps a little more. Thanks for asking.