for scientist in isro what courses i have to study please tell me

HELLO

It seems that you are interested in space science. Even I want to become scientist at ISRO(I am still 16 years old). For becoming scientist, the best option is to go for aerospace engineering as first choice of graduation course. Moreover you can do mechanical engineering, CSE and even electrical engineers. After all not all scientists observe space, some works on building up and controlling rockets and rovers too. So, plenty of choices are there but you should make sure that you score atleast 65–75% marks in graduation to be able to get a job at ISRO.