I don't mind at all!
Yes, 1 and 3 are somewhat related. Yes you can have inline styles and internal stylesheets.
Regarding point 3, here is an example. You'll notice both appear to be the same (minus the text inside). However, the HTML for the second is cleaner and less cluttered.
What happens with external and internal stylesheets is that you assign an HTML element (div,h1,p etc) a class or an id. This id or class is then used to fetch a style from the CSS.
Yes, a tag can be used for hyperlinks. It's also used for anchors, which let you navigate around the same page on click.
I hoped that helped clarify things a bit