Is there any particular different between box 1, box 2, box 3? and button, primary button, link button?

newbie-question
#1

Hi, can anybody help to explain, is there any particular different between box 1, box 2, box 3 ? what is the usage of this 3 different box?

and, also button, primary button, and link button.

image

#2

I think Axure is just providing some defaults for basic styling to get you started.