HELP HELP HELP I WILL GIVE BRAINLEST An effective summary is characterized by

an explanation of the reader's personal opinion
repetition of words from the original text
inclusion of only the most important details
a listing of the facts from the original text

inclusion of only the most important details

Explanation:

Given that Effective summary is a term. that describes the formation of a literary work into a smaller but rich content, that actively describes the content of the original work.

Hence, an effective summary is characterized by the "inclusion of only the most important details." This helps to give summary readers the main points or details of the original work.