Is "Part 1" needed if we use common app?

<p>I know a lot of schools require applicants to submit a "Part 1" of the application, and recommend that you submit it as early as possible to avoid processing delays. If these schools also offer the option to apply using the Common Application, like Cornell and JHU for instance, do we need to send in Part I with it? Or are we just responsible for the Common App and any supplement the school requires? Thanks!</p>