Answer:
The Introduction
Step-by-step explanation:
In writing a scientific paper, there are different segments with the relevant information they are to contain. These sections include the abstract, introduction, the main chapters, the results, the discussion, conclusion, and references. The Introduction segment contains relevant background information on the topic of interest. There we find a review of existing knowledge that applies to the experiment. These include past research work and citations of authors.
A statement could also be made relating the purpose of the experiment and methods used in carrying out the research. So, the paper on photosynthesis in a desert cactus would contain a review of existing knowledge in the introduction segment.