CBSE 12th

It is really very easy to recover your missed chapters. You just have to be mentally focused and firstly, just start reading your chapters and if you are stuck with any doubt you can consult anyone as nowadays there are many ways such as YouTube and even at Shiksha.com you can ask questions as per your doubts, just thinking about your problem would not work out rather, you have to stand straight and face it. At least start reading the missed chapters first.

You should take biology in class 12th (PCB) and go for some course related to environmental studies.

Overall, you need a minimum of 75% in class 12th to be eligible for counselling.

You should maintain a minimum of 75% in class 12th.
Otherwise, you will not be eligible for DTU and NSIT.

No need to worry. At this rank, she will definitely get admission in DTU.
She has fair chances of getting EE, ECE, Mech, and Civil in first round of JAC counseling.

Hi Diksha,
I think Thapar University is the best choice you can opt for, TU would be my first recommendation since you mentioned Patiala. Also even if you had not mentioned particularly the location then also in complete North India, Thapar University is considered the best for CSE.

No, you can't get admission in DTU. Because, it needs minimum 75% in boards and qualifying marks in JEE Mains to get the lowest branch in DTU.
For branch like automobile engineering, you need to score atleast 100+ in JEE Mains.

Hi, yes you are eligibile for NDA and all government job exams after 12th from NIOS.

Hi Shivam,
Please co-ordinate with your school and CBSE board, you can check on their website for notifications related to improvement exams, forms and dates.

You should go to Calcutta. It will be the best place for you.