What are four modes of writing that a historian uses

investigation,interviewed,collaboration and writing

Narration, Exposition,  Description, and Argument.

Explanation:

Historian uses four-way to write his research paper or thesis. The purpose of his writing is to explain the past. Narration helps in finding stories and tales of history. Expositions explain the motive of ideas and causes of events which have caused in past. Descriptions guides historian in representing people and places of the particular place. At last argument, historians always try to take a position on a debatable subject by giving his ideas and thought of that particular topic.

the answer is use of support  

im not sure on this one