I want to become a bio medical scientist ?which subjec i want to take please guide my question

To be a bio-tech scientist i would urge you to start building interest in biology and chemistry
coming to the graduation you can opt for a bachelors degree in bio-tech or some of the premiere engineering colleges in india offer engineering degree in bio-tech too
after graduation you can either join a research lab for work or continue pursuing research in bio-tech with masters degree
Best of luck for your future

if you have good marks in Chemistry and Biology; you should take up graduation in Biotechnology or Applied Genetics.