B.Sc

To get admission in B.Sc, you have to scored atleast 50% Marks in your Intermediate Examination. But if you want to get admission in top colleges, then for this you have to appear for the entrance examination and after clear the entrance examination you will get admission in B.Sc. The admission in this course are also based on Merit Basis according to your 12th Percentage, So if you have scored good marks in your 12th, then you will easily get admission in B.Sc Course. So, to get admission In B.Sc ourse In DU, then for this, you have to scored Miminum 55% marks in PCM subject.

Have a strong technical base in mathematics subjects.

No, you need to do your M.Sc. Also, since its is a 12+4 criteria to oursue M.Tech and apart form this you also need to have that level of string technical base which is not possible to build only through B.Sc.

Yes, you can and you can get an lateral entry in second year.

BCS in biochemistry biomedical botany chemistry.

Start preparing for the competitive exams like CAT and GMAT form the first year itself all the best brother or you can get some work ex after your graduation and later on can go for MBA.