SAT

At the time of registration, it will ask you that which subject have you studied? What is your GPA?

Hi Aparna,
The eligibility is same as for DASA students. SAT is a requirement. You can check these on the official websites. I found this link for you, please check it along with your parents and try to understand what you have to do:
https://www.youtube.com/watch?v=JIaStdeFkVY

American Universities don't see only SAT and TOEFL scores. They are interested in whole personality. They see your academic record, extracurricular activities, essay SAT and TOEFL score. You have to do your best in all in these factor.

Yes, of course!

Technically, you can take the SAT as many times as you want. There are no restrictions for registering for and taking the test. There are 7 test dates throughout the year, so the only limit that stands in your way is time. You can pick and choose which scores from which test dates you want to send as part of your college application. Regards.

Higher your SAT score, there are more chances of getting good scholarship.

You can get the previous year's SAT test papers from the College Board website.

You can take the official guide for SAT and TOEFL. Also, you can do official SAT practice in Khan Academy. You can do TOEFL preparation on edx app.

For getting admission in MIT and other top universities, like Havard you have to take at least 1500 in SAT.