Okay thanks Smiley 
also i'm still having trouble answering interrelationships and shd questions. How should the answer be broken down for 6 marks? And what's the difference between answering the two?
Sorry and thanks in advance!
They're essentially the same thing - VCAA just likes to be tricky and catch people off guard. Sustainable human development is code for the interrelationships between health, human development and sustainability. In order to actually show the relationship between one concept to the next, it needs to be sort of like a domino effect (i.e. point no. 2 is a consequence/side effect of point no.1).
I suggest knowing the human development definition very very well, so you can pick out key parts of this definition to meet the human development bit. Also do a little plan off the side of your page to make the interrelationships clear to you before you begin writing your answer. I am of the belief that if you do this, it stops you falling into a trap where you start off too narrow/run out of things to say, because you can see where your answer will end up.
Also with sustainable human development, write a nice little concluding statement like "as health, human development and sustainability have been, sustainable human development could be achieved" or something similar to show the examiner that you understand that sustainable human development is all about the interrelationships.
Also when talking about sustainability, discuss how the future generations will be affected every so often too
