Respuesta :

Answer:

Historical letter

Explanation:

edge

The type of outside source that MacGregor use in this excerpt is historical letter.

What are historical letters?

This is known to be a kind of letter that a person can traced back historically. A lot of historical letters exist in the world today that talks about various culture and traditions.

Historical letters can be gotten from:

  • Museum
  • National library
  • Life Magazine Photo Archive, etc.

The excerpt is called The Great Wave and the outside source that MacGregor use in it was a historical letter.

Learn more about Letters from

https://brainly.com/question/576523