2 Elements:
Color is being used in cooperation with Line to make colors "pop" more. Along with this, it provides and organized, yet visually appealing aesthetic to the art piece.
Color in particular, is what separates the work into sections that draw the viewer's eyes in, due to the contrast choices by the artist.
While Line, physically separates the colors, but provides the attractive composition.
(I would answer principles too, but I don't have the time currently;; Hopefully this helps though.)
C.jazz is the answer for aureus!
Can you choose more than one option?
Because a conclusion should not repeat word-for-word the introducion (this would make it actually pretty redundant), but other than this, it should be all of the remaining! (but if i had to choose one, I'd go with "summarize the main points- this would be most effective and most relevant./)
So my answer is: it should restate the thesis AND summarize the main points AND be imaginative
but it should NOT repeat the introduction word-for-word.