Hi this is by far the hardest test in the whole Salters course, I got 83/90, but I revised EVERYTHING for it.
The problem is there are a few 6 mark questions that come up on different years, I'll give you an example, I don't think DNA recombinant technology has come up for years, but it did come up in 03 and had 3 questions worth 7/8 marks in total. In chemistry by design and the AS exam chemistry of natural resources, you can kind of get away with not revisng alot because there are alot of free marks, this exam isn't like that, there are really no free marks. The RAW mark needed to get an A is indicative of this, 63/90 some years, thats shockingly low. I promise you if you learn everything on the syllabus sheets, you will do well.