What type of evidence do the authors use in this excerpt?

historical examples of political changes
personal anecdotes about the impact of social media
research studies that correlate politics and social media
social media posts about the arab spring

The correct answer is historical examples of political changes.

Explanation:

A historical example refers to the ones that are related or having the character of history, so A is the correct answer. Letter B is incorrect because the author doesn't mention his personal anecdotes as evidence; C isn't correct because the evidence doesn't introduce research studies; finally, D is also incorrect because social media posts were not included in the excerpt.

ed brushes his teeth

explanation: