Hi,
There are huge number of career options for biology students after 12 th such as  -

Giving neet exam - if you can clear the exam you can take admission in mbbs , bds , bhms and bams colleges.

Or you can do bsc in subjects like anthropology,  veterinary , agriculture,  Fisheries,  nursing , medical science genetics , etc.

Or prepare for government jobs like civil services , armed forces , banking , railway , etc.

Private jobs - lab technician , teaching field , independent researchers , private hospital , clinic , etc
Hope it helps.....