An original document containing the observations, ideas, and conclusions of an individual. It is a firsthand account presented by someone present or actively participating in the event. Examples include manuscripts, photographs, oral histories, and personal journals.

This is the description of a primary source.

Explanation:

Even though the definition of primary source can vary a bit according to different perspectives and disciplines, it can be generally defined as any record containing firsthand information. Several are the examples of primary sources: diaries, letters, memoirs, autobiographies, photographs, audio recordings, etc. Primary sources help understand an event or even an era in history.

disorders of the brain include both behavior disorders and other psychiatric illnesses. the primary difference between a behavior disorder and another type of psychiatric disorder is the presence of choice. psychiatric conditions are considered to be involuntary while in behavior disorders, choices are essential.