I believe the answer is subject matter!!
Internal is like how hot it is and external is like how much heat it gives off
OMG I've been waiting for this movie for over 2 years now, I believe its supposed to come out May 26th.
The visual representation of all the book's pages is called the page ladder.
There are various programs online for free (or you can buy them if you want) which will enable you to create this interesting thing. What the page ladder does is creates an image of what all of your pages in the documents will look like together.
