Hi Ashwini, 

There are various courses available after 12th for science stream student. 

If you opted for biology in 12th than one can go for medical field after 12th. Aoart from this you can also pursue engineering. And if you dont want to do these two than go for :

1. Architect 

2. Chartered Accountant 

3. BBA nad MBA

4. Teaching profession also after doing b.sc and than masters and phd.

There are various field which you can explore after 12th according to your interest.

Hope this will help you. All the best.