What Are the Advantages and Disadvantages of an Experiment

What are the advantages and disadvantages of an experiment?

A) Advantage: Good for gathering information about issues that are not directly observed; Disadvantage: The data were collected for another purpose and therefore the researcher cannot control what variables were included.
B) Advantage: Good for exploratory and descriptive study in a natural setting; Disadvantage: Potential for a low response rate.
C) Advantage: Group interaction may produce more valuable insights than individual surveys; Disadvantage: Research must balance roles of participant and observer.
D) Advantage: Saves the expense and time of original data collection; Disadvantage: There are none.
E) Advantage: Provides greatest opportunity to assess cause and effect; Disadvantage: The setting may have an artificial quality about it.