Answer 1

absolute path is the complete path starting from the root of the filesystem.
relative path is the path based on where your files are.

imagine you are editing an html file and want to link to another html file inside the same directory

using absolute:
C:\projects\mysite\info.html

using relative:
.\info.html

as you see relative paths are shorter and also makes them directory independent if you'd move the whole project somewhere else, absolute paths still point to the old location while relative ones use the current path and changes it 'relative' to them.

hope thats kinda understandable.