Final answer:
A strong conclusion is characterized by restating the claim or central idea and tying it back to the thesis, thereby providing closure and reaffirming the essay's main arguments.
Step-by-step explanation:
The feature that characterizes a strong conclusion is that it restates the claim or central idea. A strong conclusion ties back to the thesis, reminding readers of the main argument without introducing new ideas. It is important to create a sense of closure by re-emphasizing the main points in a concise manner, thus strengthening the effectiveness of the essay as a whole. While the conclusion may suggest areas for further research or thoughts, this should not detract from the sense of finality and reaffirmation of the central thesis.