Completely agree and sympathise with Siddhart1998 as I was also on B grade boundary so am in a very similar position. I got a borderline A*/A myself in my Biology mock (taken 2 weeks ago), but ended up only scraping a B in my ISA last June and getting lowest in the class, so I have to re-take. I was not the only instance of this happening, 3 others in my class who obtained A*s also got Bs, whereas some people in the bottom set who got Es in the mock only dropped 2 marks in the ISA. I'm obviously going to be slightly bitter but I think they seem to show a mindset of who can take questions very literally and at face value then jump through the subsequent hoops rather than who is actually a good Science student. I don't claim to be an incredible science student but I thought the results were bizarre at times!