Indian Institute of Science

Yes it is good and u can get admission through iit jam only .

Yes, you are eligible for taking admission to IISc. Note that IISc gives B.Sc. (research) in Biology Chemistry Earth & Environmental Science, Materials, Mathematics, and Physics along with a minor in any other subject. So, there are no specific courses for biotechnology, but the topic will be taught in your course of study.

Yes, you are eligible for taking admission to IISc. Note that IISc gives B.Sc. (research) in Biology Chemistry Earth & Environmental Science, Materials, Mathematics, and Physics along with a minor in any other subject. So, there are no specific courses for biotechnology, but the topic will be taught in your course of study.

For UG courses, KVPY JEE and NEET are considered for admission.

It was around 240 (for general students) in previous years.

You may check the college website for their Contact information and Ask them about the Latest Cutoff Ranks.

You can only choose one major subject, although, in some of these institutes, you might be able to do a minor, whose criteria depend upon the institute.

Mathematics, along with physics and chemistry in class 12th, are compulsory for the BSc. course.

Unfortunately, no. The website states, "The candidates must have studied Physics. Chemistry and Mathematics as main subjects in their qualifying exam along with any other subjects. "
However, don't lose hope; there are other research-oriented colleges where you can still apply.