What was one way the Mesopotamians increased their slave population? OA.
by winning them in a lottery-type contest
OB.
by capturing prisoners during wars
OC.
by trading supplies for slaves in Africa
D. by purchasing people from other countries.

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.

d. the polar jet stream   lies between the polar easterlies and trade winds should be your answer