Hello there,
Both B.Sc. in biology as well as B.Sc. in Mathematics have a good scope in both research and professional field now.
These days even in B.Sc. Biology, there are so many branches which provide good knowledge and also lay the path in the professional area for students to make their career.
B.Sc. Mathematics and related fields too are expanding there professional and research area, thereby giving students scope for the betterment of their career.
So if you are choosing B.Sc., just go through the various career opportunities available.
Good Luck!