Correct Response: C. An experiment designed to isolate the relationship between two variables requires controlled conditions to ensure that no other factors are influencing the relationship between the variables. An experiment need not be conducted in a laboratory (A), as long as it is carried out under controlled conditions. Predicting the full range of outcomes (B) is unnecessary in an experiment designed to evaluate a specific relationship. Scientific experiments seek to reveal information about unknowns so limiting the scope of the experiment to known facts (D) would not aid in the evaluation of the relationship being investigated.
