A biological psychologist would be most interested in conducting research on the relationship between

A. Neurotransmitters and depression

Explanation:

The complete question is:

A biological psychologist would be most interested in conducting research on the relationship between:

A. neurotransmitters and depression.

B. skull shape and bone density.

C. self-esteem and popularity.

D. genetics and eye color.

A biological psychologist is a person who is interested in studying the behavior of human beings and tries to understand the psychological causes underlying the behavior along with the various genetic and chemical factors that affect the behavior. It is believed that the genetics and the chemical factors of the brain together affect the psychology of a person and ultimately affect the behavior. Thus, they establish a link between the physiological processes and the psychology of a person. Therefore, in case a person is suffering from depression which is a psychological problem a biological psychologist would try and understand the chemical changes in the brain and thus would study the neurotransmitters.