Hy thr,Bsc is UG Degree after 12it is Proceeded casual from PCM Or BZC ,U should have 50 %marks in each subject for getting into it , its 3year degree which is provided At the level of Honours also in universities,And many colleges Provide admission into it if U are from Biology u can Apply for
Bsc (BZC)
B sc Ag
Bsc biotechnology
Bsc Textiles
Bsc Microbiology
Bsc  Physiotherapy
Bsc Food dietics
BSc Nursing
BSc Food Processing
BSc Honours
BSc food Packing
BSc Forensic science
BSc  Medical science
Bsc computer science
CSIR  (Bsc Ag)
There are many more Courses if u want to get in a good field better go with Any special course over just doing bsc Simply
Universities Such as BHU ,DU JNU ,Bhopal university graphic Era Deemed University ,MGKVP,  And Lot morr offers admission in These Courses they conduct entrance test and According to the cut off they offer admission in campus or affiliated College
All these courses are Good on the basis Work and job. U can apply for these courses via online Mode and they will ask u to clear the entrance test ,Followed by ur 11,12 syllabus.they are few more colleges in which u can apply direct admission. E.g Sharda,LPU,Amity  etc   (There Fees Rates could be High )
And u don't have to struggle with the subjects if u study Smartly

I'm totally confused what can I do??  So 

Hello aspirate 

Procedure for Admission in B.Sc course depends on the institute you want to do the graduation from. The basic requirement for this course is 10+2 with science as subject having minimum 50% in subjects. 

Also for some institutes like BHU, DU(from this year)  have their own entrance exam and if you qualify that exam then only you can get admission there. 

There are also many colleges / universities in India where you can directly take admission on 12th merit without any entrance exam. 

Any problem you can ask more

Hey !
Bachelor of Science is a 3-year full-time undergraduate course which is divided into 6 semesters. Candidates who have completed their Higher Secondary examinations (10+2) with minimum 50% marks from a recognized educational board with Science stream can opt for Bachelor of Science. The percentage may vary from state to state and from Institute of the institute.Some major streams available in this degree are Chemistry, Animal Biology, Environmental Science, Cell Biology, Human Biology, Mathematical Modelling, Material Science, and Geography, Natural Science, Plant biology.
Hope this helps
All the best !