The Best Description of the Probable Role That Genes Play

Multiple Choice

The best description of the probable role that genes play in behavioral disorders is that

A) a single gene causes each of these disorders.
B) the same disorder may be caused by a single gene in one individual, and solely by an environmental factor in another.
C) single genes with major influences as well as small inputs from common gene variants contribute to susceptibility to behavioral disorders, perhaps requiring environmental triggers.
D) these genes increase the risk of infection, which directly causes the behavioral disorders.
E) variants of the same gene underlie major depressive disorder, bipolar disorder, anxiety disorder, eating disorders, and schizophrenia.