What is the difference between the_content and content.php?

the_content is a template tag that displays the post content entered into the WYSIWYG editor in the admin. 

content.php is a partial file, like we set up in the "Make a blog page" challenge.

You can use get_template_part (); to load a template partial like content.php into a template, like index.php. Because a partial is a reusable piece, you can call it in lots of different templates. This saves you from repeating a bunch of code unnecessarily and it makes updates much easier!

So now you know that you can call 'the_content();' inside your content.php template partial and be perfectly content about it! Haha!