Final answer:
Source A, from the Fiber Farms Cereal Company, may have a commercial bias and could be less credible, while Source B from the Professional Medical Practitioners of America is likely credible and highly relevant to the topic.
Step-by-step explanation:
When evaluating the credibility of a source related to a research project on the role of dietary fiber in good health, you need to assess the authority, objectivity, and relevance of the source. Source A, "Understanding Your Fiber Needs" from the Fiber Farms Cereal Company's website, might be biased as it comes from a company with potential commercial interests in promoting fiber consumption. While it may contain useful general information, its credibility could be compromised by the company's intent to sell a product.
Source B, "Fiber and Your Health" from a pamphlet published by the Professional Medical Practitioners of America, is likely highly credible and specifically relevant to the research topic since it is published by medical professionals without apparent conflicts of interest. It would likely offer expert insights and trustworthy information on dietary fiber and its impacts on health.
Moreover, corroborating the findings with additional sources from peer-reviewed academic publications or reputable health organizations can further strengthen the research paper and ensure comprehensive coverage of the topic.