Maybe with a diploma, your chances of being accepted for a
second diploma course will be higher?
With 17, cannot get into a diploma course in biomedical science
ah?
If you get a related diploma, will you be able to study for a
biomedical science degree or not?
I don't know erh hehe me never go poly. 
Why do you want to go into biomedical science... I think I read
somewhere that degree holders usually only become lab assistants...
dunno is it true...