Vincent is designing a research study as part of his master's thesis. he wants to do a laboratory study where he can control as many variables as possible, but he is concerned that his findings will not generalize very well from the laboratory setting to the real world. in technical terms, vincent is concerned about the of his study.

External validity

Explanation:

By controlling al the variables possible, and not generalizing some to global situations, or environments, he is correct to be concerned that his study could  not have a general consensus outside the limits of his study, since it might not be replicable across other groups of people, situations, environment, stimuli, or times, this is called EXTERNAL VALIDITY, or the validity of the same study under influences of variables outside of the study's ranges.

answer; ///i believe that the correct answer is (a) specialized cells)