Science

Pass in 10+2 from any stream with 55% marks in aggregate. The complete course is covered in 3 years. Search for colleges and before all of this, think what you want to become like ATC, etc.

Refer college websites like Fergusson College, etc and see their criteria.

Depend on college. Fergusson College has something around 3L.

https://www.shiksha.com/science/colleges/b-sc-colleges-Udaipur
Please follow the link that I am sharing here. It will help you in getting a better college.
Good luck.

The previous paper can be downloaded through DU's website.

General/OBC category - 190 marks. After that your candidature may be considered for paid seat in BHU main campus as well as for Rajiv Gandhi South campus RGSC.
But, the cut off may get low this year because of re- examination,the students may not appear in same number as earlier and the level of ques

Ask your question clearly.

In order to get admission, you need to register yourself to the college website. The admission is based upon the marks obtained in 10+2.