and please tell me what is the procedure of selection?
Procedure to join ISRO after B.tech in Biotechnology:-
You need to fill the GATE form at the earliest and exam will be held in February. After filling up the GATE form, you will get a registration number and you need to give this number whenever you are feeling any PSU form.
Keep checking the official site of ISRO for any latest openings, or you can also Keep checking the site.
You can get these jobs in ISRO:-
BSNL
NTPC
BHEL
BEL
SAIL
POWER GRID
BPCL
HPCL.