hi,

see there is many streams available for bsc course, and in first year you need to study about mathematics,  physics and chemistry, mathematics is common to all branches of bsc course, now since you are going to study about a particular subject you also need to learn about the relative subjects .

there is general bsc and bsc honours.

for bsc honours there is streams of physics, mathematics, chemistry, zoology, micro biology, biotechnology, electronics science, computer science etc.