CBSE 12th

Congratulations! You scored very good in 12th. You will definitely get admission for Bachelor's.

Minimum marks should be atleast 60% in PCM.

Students seeking admission to B.Sc program should have an educational level equivalent to a pass in high school (10 + 2 years of schooling). This is all.
Good luck.

Yes, of course, it has got a wide scope across the world. You can do B.Sc in audiology.
Good luck.

Hello,
I am sorry but you won't be eligible to apply in DU. Your best four percentage should be more than 85% to apply for good courses. Also, if you are from General caste, then things will be further complicated for you. Less famous courses like B.A. Sanskrit or Hindi Honors only have around 65-70% cut-off. But there's always hope, my friend!
You can apply to private colleges all over India. Amity Noida will be a good choice for you. All the best!
Feel free to ask more.
Follow for more updates.

IIM offer post graduation courses so you first need to pursue your graduation and ensure that you score minimum 50% marks and then compete in CAT entrance test) and try to achieve a score of more than 98 percentile to get a call for Personal Interview (PI). On successful clearance of it, you will get admission. Offlate IIM Indore also offers an integrated course of BBA & MBA. You can check on their website on the admission requirements.

Go to the link below to find the list of engineering colleges and filter your choices according to you like location, specialisation, courses, etc.
https://www.shiksha.com/engineering/colleges/colleges-india

None of the private colleges has less expenditure. If you're thinking of going to a private college, then you must be ready to pay around 80k-1.5 lakh for academics ( excluding other living charges).
If you are from ST category, then you might have some chance of getting admission in University of Delhi.
Hope this helps! :)