first of all your background should be of science in 12th standard. and as the collgese have there own cut offs and the candiates who fill the criteria will get the admission in bsc. and normaly there is no such enterance exam in it.

Dear student

The prucedure for admission in B.Sc courses is different for different universities in India. Some university admit students on the basis of class 12th marks like University of Delhi while other universities organise separate entrance test for it like BHU, AMU etc.

Hope this helps

All the best!!!