Teaching of Chemistry, Physics and Biology in one class

[chrisd1997]

Only the top 2/3 sets in my school are taught seperate lessons of Physics, Chemistry and Biology after year 7 (first year senior school). So the other 7/8 science sets get one lesson with Chemistry, Physics and Biology on different terms, don't you think this will decrease there chances of GCSE when they do them next year?

Thanks in advance,
Chrisd1997