Chris learns her vocabulary words while listening to upbeat, happy music, and is then better able to remember them later if she is happy. this is called

1) d

2)c

3)b

4) a

5)c

6) c

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.