It can vary, could be something from the first major unit of study about Issues In Australian Environments (like air pollution, soil degradation, spatial inequality and all that stuff) or from the second major unit of study about Austra and it's Regional and Global Context (something about the links about foreign aid, trade, migration etc., a question about human rights).
But seriously, it's pretty easy to bulk up an answer. Like e.g for aid you can go on about the different types, the costs and benefits, the government agency AUSaid, NGO's, what areas the aid can improve like health and education, throw in something about active citizenship and some terms and you're sweet.
I'm just about to switch into History and I'll probably have to do more work in History than Geography. I came an easy convincing first in Geography. Just look at the past papers. But I bet in History already, the long response will msot likely be on Vietnam or the 50's or something.