my two science which are biology and chemistry for unit 1 which are in 16/17 days time .. my unit 2 exams are in 1/2 june is it too late to do past paper
Not quite, as long as you can start doing them now and constantly look over them then you can still get a B or an A. Assuming this is for AS, it'll be fine and don't worry about it.
We're probably doing the same exams since my bio and chem exams are like on that date too. F211? F321? Etc
And I don't think it's too late to do exam papers just make sure you go over the mark schemes as well. At least you have time!
And well I still haven't gone over the end part of the unit 2 syllabus in bio, so I probably won't have time to do past papers. I'm too busy revising for my maths exam and RS which is next week. So nerve wracking.