Keep in mind the marking guidelines and sample answers for trial examinations may not necessarily be indicative of how the exact same questions would be marked for the HSC examination itself.
Use it as a guide as some of the sample answers / marking guidelines are horrible!
Example in this years CSSA Physics paper, the verb used for a 6 marker was discuss, but according to the marking criteria, all you needed to do was describe stuff to get 6/6 -- I changed this marking guideline along with several other teachers who used the CSSA paper.
So, be careful!