No..... If they're illegal, what's the point?
D. the balls were dropped from different heights
Answer: Option 'a' is correct.
Explanation:
Researchers can isolate a single factor and examine the effect of that factor alone on a particular behavior through use of a choices is an experiment.
As experiment means when a hypothesis is tested scientifically and check when the cause is changed what would effect that factor alone.
whereas correlational study is the study of two variables understand it and develop the statistical relationship between them without affecting from any variable.
Hence, option 'a' is correct.
