Question

The results of studies investigating the role of biological factors suggest that depression is caused by __________. select one:

a. variations in the serotonin transporter gene
b. increases in polypeptide y in the brain
c. decreases in the levels of gastric ghrelin
d. unusual elevations in both dopamine and glutamate levels

Answer 1

I believe the answer would be A.

Answer 2

The results of studies investigating the role of biological factors suggest that depression is caused by variations in the serotonin transporter gene.
Serotonin transporter gene is a gene that controls how many serotonin re-uptake transporters will be produced. It has been shown that mutations in this gene are linked to depression (depression has been linked to low levels of serotonin).