One of the advantages of the experimental method is that a. it allows information about large numbers of people to be gathered. b. all types of behavior are easily studied in the laboratory. c. clear cause-and-effect relationships can be identified. d. it allows the investigation of rare or unusual problems or events.

what is the other part to the question

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.