Here's why:
* Introduction: Introduces the topic and states the main idea (thesis statement).
* Body Paragraphs (3): Provide supporting evidence and arguments for the main idea.
* Conclusion: Restates the main idea in a new way, summarizes the key points, and leaves a lasting impression on the reader.
The conclusion is where you bring everything together and solidify the main idea in the reader's mind. It shouldn't just repeat what was said before; it should synthesize the information and demonstrate the significance of the argument.