Final answer:
The most effective summary would include the sentence 'Somewhere along the journey, Earhart and her plane disappeared.'
Step-by-step explanation:
The sentence that should be included to create the most effective summary is: Somewhere along the journey, Earhart and her plane disappeared. This sentence provides a concise summary of the main event related to Earhart's attempt to fly around the world. It captures the mysterious disappearance of Earhart and her plane, which is a significant part of her story.
Learn more about Amelia Earhart's Disappearance