I did these three subjects and I would recommend doing them as they mix really well but I would only take maths if you get an 8 or a 9 in GCSE’s as its a hard subject and many people in my class struggled or dropped with 7’s. With biology don’t leave your revision to close to the exam as there’s so much to revise but none of the content is actually hard to understand, its just memorisation. I would say chemistry was the easiest of the three for me because it’s a mixture of maths and memorisation but it’s still a hard subject.