get dotpoints. its bloody good. it goes through each and every dot point and asks u a heap of questions on each plus answers in the back (including answers to longer response questions - it doesnt just say 'ask teacher'). i think the physics one also has summaries.
lol sorry. now i feel like an arse. thought he was talking about physics for some reason (probably cos i havent done any study for it). but hey if u can find a dotpoints earth enviro im sure its good too!