How do historians make sure that they do not inject their own biases into their work?

Historians should produce evidence-based information.

Explanation:

The historical research not only considers and discusses the meaning of the sources but also their implications. Historical researchers recognize that one point of view is not completely right, there is a need for more information to reconstruct the events in question, and implies that the reader does not follow the author blindly. Historians need to refrain from their opinion and based their research on historical methods. Historians can provide reliable and persuasive scholarships by submitting their work for peer review and the academic world.

answer; (a) he was a u.s senator for 38 years;