What describes a source that is knowledgeable and unbiased?

The term that best describes a source that is knowledgeable and unbiased is "credible." A credible source is one that provides trustworthy and accurate information. This credibility often stems from the author's qualifications, the evidence provided to support claims, and the reputation of the publication or organization behind the source. Credible sources are essential in research and academic settings as they help ensure that the information being used is accurate and dependable.

While "impartial" also suggests a lack of bias, it does not necessarily convey that the source is knowledgeable. A source can be impartial yet lack the expertise or depth of knowledge required to be credible. Trustworthiness in a source encompasses both a knowledgeable perspective and an unbiased representation of information, making the term "credible" the most fitting in this context.