Answer:
The correct relation between Vocabulary terms and definitions is as follow:
a. treatment → a. experimental conditions imposed on the subjects
b. observational study → a study in which data is collected without anything being done to the subjects.
c. retrospective study → d. a study in which data from the past is examine
d. experimental units → c. The people, animals or things on whom experiments are performed
e. experiment → e. a study in which a treatment is applied and responses are observed
