A secondary source is one that is written by an individual who did not witness the actual event.
A primary source is one that is written by someone who is present at the event.
In this question, there can be several correct answers. Here are some examples of some correct answer choices:
1) A history textbook used in a high school class.
2) A biography about Abraham Lincoln's life written by a historian from the 21st century.
3) An interview with a historian who has studied Lincoln but was not alive for his assassination.
The United States obtained no intelligence hinting at a surprise attack in the Pacific.
A) all native Americans tribes to the east were required to move onto one large reservation.