I'm the editable paragraph of the master page and can be edited on child pages.
The component is defined and placed here, in a non-editable area of the master page. By definition non-editable parts of the master page will be the same on all its child pages. It doesn't really matter that the component has editable areas. However we change it on the master page, this is how it will look on all child pages because it is in the fixed part of the master page.
I'm a component, defined on the master page. The content of this text and individual list items is editable.
Here we have an editable section of the master page. That means that the content can be changed on child pages. Here we added an instance of our component. Because it is in the editable section every child page can have its own version of the content, including component instance.
Plants: