If you want to continue in the academic field you can go for the post graduation (Master of science) after Bachelors of science for the same subject, completing which you can apply for various National level PhD programmes like NCBS, CSIR-NET -JRF, ICMR-JRF, TIFR etc.

If you are not interested in the academia, you can go for the civil services (IAS, IFS ) also you can try in several govt. jobs like bank PO. SSC (staff selection commission) can be another option.

Also if you are already in your first or second year of graduation and passionate about science and interested in research you can give TIFR and IIT -JAM (life science).

Hope you find it helpful

let me know in the comment box if you are having any further doubts

thanks

Good Luck!