Answer: A peer review
Explanation: It is a peer review, because in this the researchers or scholars of the same field examine the work and results of other researchers. This process is done before publishing the work.
Journal is a collection of papers, which can be of same or different topic or concept. But they are somewhat part of the same field. Different subjects have their separate journals, for the ease of the readers. Conclusion is a part of the paper or thesis or scientific report. So does control group, it is part of the experiment.