What are the differences between starting a review and leaving a single comment on GitHub?

When starting a review on GitHub, you are providing a detailed analysis of the code changes, suggesting improvements, and discussing the overall quality of the code. On the other hand, leaving a single comment is a brief remark or feedback on a specific line of code or a particular aspect of the project. Reviews are more comprehensive and involve a deeper evaluation of the code changes, while comments are more focused and specific.