oh thanks alot jessie !
umm yeah sorta just wanted some model examples that could be used in the exam if they asked
just so theyre clear examples and such so if you could ! 
but that was great though
thanks =]
Hmm, well, basically all you need to do is use the explanations I've provided, but apply it to the picture they've included in the exam. So:
Linear Perspective:
"The two lines parallel lines of the ____ in this above picture appear to converge (meet) as they recede into the distance."
Texture gradient:
"The ____ in this picture is perceived as having more texture or being 'more detailed' close up, however as the distance increases from the viewer, the ___ becomes more uniform, finer and smooth (less detailed.)"
Relative size
"The ____ in this picture which produces a larger image on the retina are perceived as being closer, whereas the ____ which produces a smaller image on the retina is perceived as being further away"
Height in the visual field
"The _____ which is drawn closer to the horizon is perceived as being further away, whereas the ____ which is drawn further away from the horizon is perceived as being closer to the viewer"
Interposition
"The _____ which partially obscures the _____ is perceived as being closer to the viewer"
If it isn't a specific example, and it's just asking you describe the principle in general, insert "object/s" or whatever.
I hope that's what you were after :S